Definition of Variation Order

A variation order is issued by Company to Contractor, as an instruction to vary the scope of the contracted work. Variations may be changes – either increases or reductions – in the amount, type, quality, execution or schedule of the work.

The Contractor will submit an estimate for the work, unless both parties agree that this is not necessary.

Sometimes (not always) the change is proposed by the contractor, in a Variation Order Request (VOR)

The contractor is expected to carry out variations on request.
For this reason, variations should not exceed a ‘reasonable’ proportion of the work to be done.
It would not be 'reasonable' to have a contract lasting one month, then add variations for several more years.