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 screen will appear listing the indexes that are available. Select the index you wish to open by clicking on the index name.
Further sub-indexes may be presented, select the index relevant to your form. To delete users from a form you click on the 
icon on the form you wish to delete the users from. For example, the form is Air Conditioning and is assigned to Sasha.
A new window will appear. You then click on 
next to the user, click OK to confirm.
If you are unable to follow these instructions, you may not have the required user permissions. Please contact your Site Administrator.