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.
Click on the relevant index you wish to delete the form from, for example Bodyshop.
Within the index you have selected there will be further sub indexes. Select the relevant sub index, click the 
icon on the form you wish to deactivate.
A new pop up will appear, click on Deactivate Form.
If you are unable to follow these instructions, you may not have the required user permissions. Please contact your Site Administrator.