From the xCenta Dashboard, click on Tools > Admin in the top right of the screen.
From the administration screen, click on Manage Site Indexes and Forms.
A new page will appear, click on the relevant index.
A new page will appear, click on the relevant sub index, find the relevant form and click the 
icon.
A new pop up will appear, click Reactivate Form.
If you are unable to follow these instructions, you may not have the required user permissions. Please contact your Site Administrator.