Change Orders allow you to add or delete items in an approved project. Change orders can be created and managed via the Change Orders tab at the bottom of the Project Explorer.
Change orders are not created automatically. Change Order functionality is not available until you approve a project. You will be prompted to create a change order when you attempt to delete or add items in an approved project.
To approve a project, make sure the project is checked out to you and then click the Mark Project as Approved button in the ribbon of the Project Explorer.
Check out this article for more details.
A checkmark will be displayed in the "Approved" column in Project Explorer.
You can mark an approved project as Unapproved by clicking the Mark Project as Unapproved button.
If you mark a project as unapproved, all revisions and change orders will be deleted.