Definition of Estimate (EST)
An ESTimate contains a description of the work to be done that is related to a Variation Order VO.
It also gives details of the schedule, milestones and resources required to do the work, as well as the cost and schedule consequences of the variation. This enables the company/client to evaluate the consequences of the change.
For example, if a change proposal is raised by the company, they may issue a VO for a small amount so that the contractor can consider what the cost and consequences of the change would be.
Their reply would be the estimate.
The company would then consider whether to go ahead - and would issue another VO if they decided to go ahead.