How to restrict the access to the EBS application to a few users only

 Hello,

We are using Oracle Ebusiness suite 11.5.10.2 , database 9.2.0.8.  In a few weeks , we will need to implement a lot of modifications in production.  In order to do that, I need to be sure that most of the users won't have access to EBS but the IT Users and the Super users should have access to modifiy and implement the modifications.

What are the possibilities to restrict the access to the EBS application to a few users only for a while and then let all other users have access again after completing the maintenance ?

Thanks

Caroline