Changing accountant worries people more than it should. The usual fear is losing your history, getting stuck mid financial year, or damaging a relationship. In practice the procedure is well marked out and takes place between professionals, with little involvement on your side.
- Can you leave mid-year
- The right moment in the accounting cycle
- The procedure between professionals
- What the previous firm must hand back
- The case of unpaid fees
- The handover checklist
- Five signs it is time to change
- What a change costs
- Tax mandates, the classic oversight
- Changing when the relationship is already tense
Can you leave mid-year
Yes. No legal provision obliges you to stay with a firm, and free choice of professional is a basic principle of the relationship.
What binds you is the contract you signed. The engagement letter may set a term, a notice period and the conditions for ending the relationship. That is the first document to reread, before you even contact a new firm.
If your engagement letter sets three months' notice, observing it avoids a pointless dispute. If it sets nothing, reasonable notice in writing remains good practice.
The right moment in the accounting cycle
Technically, a change is possible at any time. Some moments simply cost less friction.
The best window is after the annual accounts and the corporate income tax return have been filed: the financial year is closed and settled, and the new firm takes over a clean file. For a company closing on 31 December, that generally falls in early autumn.
The worst window is the eve of a deadline. Changing three weeks before the annual accounts are due forces the new firm to work under pressure on a file it does not know, and that is paid for, in fees and in the risk of error.
Changing mid financial year remains common. It simply involves a handover in progress, with an opening balance supplied by the previous firm.
The procedure between professionals
This is the point that reassures clients most: you do not have to manage the transition yourself.
Once your new firm is chosen, it contacts the previous one to inform it of the handover. The ethical rules applying to ITAA members govern that relationship between professionals and aim at a proper transfer of the file. Practice is for the notification to be in writing, and registered post gives it a certain date.
The previous firm then states whether there is any impediment to the handover. That is also when it flags any fees still unpaid.
Your role comes down to three things: signing the new engagement letter, notifying the outgoing firm in writing that the relationship is ending, and giving access to the tools and data you control.
What the previous firm must hand back
The documents that belong to you remain yours: purchase and sales invoices, bank statements, contracts, supporting documents. They are handed to you, or passed directly to the new firm.
To those are added the items produced under the engagement and needed for continuity: trial balances, account histories, the last returns filed, depreciation schedules, and the opening balance if the change happens mid financial year.
Good practice is to draw up a list of the documents transferred, dated and signed by both firms. That traceability protects everyone: it stops a missing document becoming nobody's responsibility six months later.
One practical point often overlooked: if your accounts live in software licensed in the firm's name, check early in what form you get your data back. A usable export cannot be taken for granted.
The case of unpaid fees
An unpaid invoice does not prevent you from changing firms. It remains owed, and it will be claimed.
The difficulty arises when the previous firm makes handing over the documents conditional on payment. The useful distinction is between your own documents, which you are entitled to recover, and the work carried out by the firm.
In practice, a disagreement of that kind is better settled by direct discussion than by a standoff. If the deadlock persists, the ITAA has contact points for disputes involving its members.
The handover checklist
- Reread the current engagement letter: term, notice, exit conditions
- Check the new firm's registration in the ITAA public register
- Sign the new engagement letter, having checked the scope and the fees
- Notify the outgoing firm in writing that the relationship is ending
- Let the two firms arrange the handover between themselves
- Obtain the dated and signed inventory of documents transferred
- Recover a usable export of your accounting data
- Update mandates and powers of attorney, particularly tax ones
That last point is the most often forgotten. The mandates given to the previous firm to act with the administration must be revoked and granted to the new one, failing which correspondence keeps arriving in the wrong place.
Five signs it is time to change
- You get no reply within a reasonable time, including before a deadline
- You discover your figures only at year end, having never been alerted during the financial year
- Invoices regularly carry items you do not understand and that were not announced
- The firm failed to anticipate a major regulatory change, such as mandatory electronic invoicing since January 2026
- You have changed scale and the firm has not kept up
A single one of these signs does not necessarily justify leaving. Three of them do.
What a change costs
The change itself is not billed. What is billed is the handover work, and it depends entirely on the state the file arrives in.
A file taken over after a close, with accounts filed and a clean trial balance, needs little extra work: the new firm integrates the opening balances and gets going. A file taken over mid financial year, with entries to restate and documents missing, is paid for in hours.
Ask the new firm to estimate that handover cost before you sign, and to write it into the engagement letter. A firm that quotes an attractive fixed price without a word about the handover will bill the difference later.
One point not to overlook: if you leave mid financial year, the previous firm may bill the work already done on that year, even though no return has yet been filed. That is legitimate, and one more reason to prefer leaving after a close.
Tax mandates, the classic oversight
Your accountant acts with the administration through mandates you have granted: filing VAT returns, access to your electronic files, tax correspondence.
Those mandates do not lapse because you have changed firms. Until they are revoked, the previous firm keeps access and continues to receive notifications, while the new one cannot act.
Revoking and re-granting the mandates is part of the handover, and the new firm knows how to do it. Someone just has to see to it: it is the most frequently forgotten step, and the one that produces the most unpleasant surprises, from tax post arriving in the wrong place to a return nobody files because each side assumes the other is handling it.
Changing when the relationship is already tense
A departure goes badly mainly when it is announced badly. Two precautions cut the risk considerably.
The first is to put everything in writing. A letter notifying the end of the relationship, the request to return the documents, the signed inventory: every documented step is one less difficulty if tempers rise.
The second is not to mix subjects. A disagreement over an invoice is settled on the ground of that invoice, not by withholding documents or refusing to share a balance. If the situation stays blocked despite that, the ITAA has contact points for disputes involving its members, and that is the route to take first.
Sources
- ITAA, ethical framework and contact points
- Law of 17 March 2019 on the professions of accountant and tax advisor
Information verified on 29 August 2026. The concrete terms of a handover depend on your engagement letter and on the ethical rules in force; in the event of a dispute, contact the ITAA.
Further reading
- What does an accountant cost in Belgium in 2026?
- Accountant or tax accountant: what is the difference?
- Compare Belgian accounting firms
This article is for information only. It does not replace the advice of a registered professional on your specific situation.