How to remove project server integration in AX 2009?

Hello.

I have deployed and running AX 2009 with MS Project Server 2007 integration successfully.

Now I want the AX to integrate with a different Project Server.

When I go to AX=>Project=>Setup=>Microsoft Project server integration=>Configure Integration

and then try to delete I get following warning message:

The integrated project server application Application ID cannot be deleted. Entities exist that are integrated to the application.

How do I remove integration and re-integrate?