In project management, change orders are also called variations or variation orders. Any modification or change to works agreed in the contract is treated as a variation.
These modifications can be divided into three main categories[1]
A change order is work that is added to or deleted from the original scope of work of a contract. Depending on the magnitude of the change, it may or may not alter the original contract amount and/or completion date. A change order may force a new project to handle significant changes to the current project.[2]
Change orders are common to most projects, and very common with large projects. After the original scope (or contract) is formed, complete with the total price to be paid and the specific work to be completed, a client may decide that the original plans do not best represent his or her definition for the finished project. Accordingly, the client will suggest an alternate approach.
Common causes for change orders to be created are:
A project manager then typically generates a change order that describes the new work to be done (or not done in some cases), and the price to be paid for this new work. Once this change order is submitted and approved it generally serves to alter the original contract such that the change order now becomes part of the contract.