To move a project out of archive, select the project from the archived project list on your Projects page. Navigate to the Project Setup page in the left hand menu bar.
From the Project Setup page, select the Phase you wish to move the project to. Please note that you will only be able to move a project back to Prospect status if it was archived while still in Prospect phase. If a project has ever been made active, you will not be able to return it to Prospect status.