My scenario is that I created the App and the client gave me the access to their developer's account. I only have access to their Certificates, which I downloaded. Both Developer and Distribution Certificate.
I also have access to their itunesconnect with which I can upload the App.
My question is how will I be able to use those certificates and upload the App on AppStore. Client's App ID is different than mine, so I guess I'd have to change mines and create a new package.
Would I use client's certificates and create provisioning profiles through my developer account?