I had a Promoted app and assinged to operator, which the appplication Display name needed to be updated, but i cant find a way to edit the application details although I deregister the app. Please suggest me the solutions.
You cannot change the configuration of a promoted application. You would need to create a new version and the to trigger the process again. However, the Operator Cockpit already offers operators the ability to change the Display Name and/or Icon for the application. So there is no need to update it on your side.