Which SDK are you using?
In general It is possible but not recommended.
Since SDK have information such as App ID, App Key, Server Location, etc in static variables, Switching the app in multithread environment could causes unexpected result. (ex. API call is made for App A, but it is switched to App B before making actual request to server and turned into request for App B)
You may need control in your app that ensures there's no unfinished async API calls when you switch the App.