Within Teamwork, you can mark a milestone as complete at any time.
You can complete a milestone directly in the Milestones tab of your project, or when viewing an individual milestone.
To complete a milestone, select the checkbox to the left of the milestone name.
Once a milestone has been marked as complete, you will be able to view it in the Completed tab of the Milestones area.
Note: Milestones must be completed individually. Completing all associated task lists does not automatically complete the milestone.
You can also reopen a completed milestone by deselecting the checkbox to the left of the task name.
Milestones can also be completed or reopened in the Everything area of your site.
For more information, see: Adding a Milestone