to move app to another user; to change app as shared app

to move app to another user; to change app as shared app

I have two questions:
- is it possible to move an application to another user: I made an app, I share the app, the user I shared with keeps the app and I delete it ?!?
- if a app is shared as developer, is it possible to make changes? (show as grid, change something and save it)