What variation means
A variation changes the terms of a contract that is already running.
It is an agreement in its own right, so it needs the same ingredients. Both parties must agree, and there must be consideration, meaning something of value moving each way, unless the variation is made by deed.
That consideration requirement causes practical difficulty. Where one party gets more and gives nothing, the variation may be unsupported. A contractor agreeing to finish earlier for the same money, or a client agreeing to pay more for the same work, are the classic examples, and the usual answers are to give something small in return or to record the change by deed.
A variation is different from a waiver. A waiver gives up a right on one occasion and the term survives. A variation changes the term permanently, for both sides, going forward.
How it is used
Variations are the everyday reality of any project of length.
A construction contract where the client adds two rooms. A software build where the scope expands after the first demonstration. A consultancy where the client asks for an extra workstream. A supply agreement where volumes and prices are renegotiated. A lease where the parties agree to change the rent review date.
Well run contracts anticipate this and include a variation or change control procedure: how a change is requested, who may approve it, how the price and timeline are adjusted, and that it must be in writing and signed.
Using that procedure is the whole point, and it is the step that gets skipped. Work expands over WhatsApp, everybody is busy, and nobody produces a change note. The client later says the extra work was always included. The contractor says it was not. Neither has anything in writing, and a job that went well ends in a dispute over the final invoice.
Key features
- An agreed change to a contract already in force
- Requires agreement of both parties, and consideration unless made by deed
- Different from a waiver, which relates to one occasion only
- Well drafted contracts contain a change control procedure
- No oral modification clauses require variations to be in writing
- Unrecorded scope changes are the commonest cause of final account disputes
How this works in Nigeria
The most common Nigerian variation problem is not legal, it is documentary. Scope changes are agreed in conversation, on a site visit or in a message thread, and nobody writes a change note.
The practical fix is small. A one paragraph change note stating what is being added, what it costs, how it affects the timeline, and signed or confirmed by both sides, prevents almost every final account dispute. It can be an email, provided the other side confirms it.
No oral modification clauses are common in Nigerian contracts and are worth understanding. They provide that no variation is effective unless in writing and signed. They are useful, and they are not absolute: a clear course of conduct showing that both parties actually agreed and acted on an oral change can still be argued, particularly where one side has performed the varied obligation and the other has accepted the benefit.
So the clause is best treated as a reason to write things down rather than as a guarantee that undocumented changes never bind.
One more Nigerian point: where the original contract was made by deed, or concerns land, the variation should generally follow the same form. A significant change to a registered instrument may itself need stamping and registration.
Variation vs waiver vs new contract
Three ways an arrangement changes, with different consequences.
A waiver gives up a right on a particular occasion. The contract is unchanged and the term survives for next time.
A variation changes the term itself, permanently and for both parties, and requires agreement and consideration or a deed.
A new contract replaces the old one entirely. Where the changes are extensive, this is cleaner than a variation, because a heavily varied contract becomes hard to read as a whole and inconsistencies between the original and its amendments get litigated.
The practical test is volume. One or two changes, vary. A change to the commercial core, or a fourth amendment, restate the whole agreement. The cost of a restated contract is an afternoon. The cost of arguing about which of five documents governs is considerably more.
Limits and risks
A variation binds only where both parties actually agreed. A change imposed by one side is a breach, not a variation, however firmly it is asserted.
The consideration requirement can defeat a genuine agreement. Where one party gives nothing in return, the variation may be unsupported unless made by deed.
Authority is another gap. A variation agreed by somebody without authority to bind the company may not stand, which is why change control procedures name who may approve.
And variations to instruments concerning land can require the same formality as the original, including stamping and registration, which parties often overlook when amending a lease or a deed.
Worth knowing
Write a one paragraph change note for every scope change, stating what is added, what it costs, and the effect on the timeline, and get the other side to confirm it in writing. Nigerian projects most often end badly not over the work but over the final invoice, and that paragraph is what prevents it.
Questions people ask
What is a contract variation?
An agreed change to a contract already in force. It is an agreement in itself, so it requires the consent of both parties and consideration, unless it is made by deed.
Does a variation need consideration?
Generally yes, unless it is made by deed. Where one party receives more and gives nothing in return, the variation may be unsupported, so the usual answers are a small reciprocal concession or a deed.
Can a contract be varied verbally?
Sometimes, but it is a poor idea, and many contracts contain a no oral modification clause requiring variations to be in writing and signed. Even where such a clause exists, a clear course of conduct can be argued, which is another reason to write it down.
What is a change control procedure?
A contractual process for handling scope changes: how a change is requested, who may approve it, how price and timeline are adjusted, and the requirement that it be recorded in writing.
What is the difference between a variation and a waiver?
A waiver gives up a right on one occasion and the term survives. A variation permanently changes the term for both parties going forward.
When should I restate the contract instead of varying it?
When the changes are extensive, when they touch the commercial core, or when several amendments already exist. A heavily varied contract is hard to read as a whole, and inconsistencies between amendments get litigated.