To re-sign an iOS app with another developer account, ensure that the following are in place first.

1. Distribution certificate of the other developer account
2. A provisioning profile from the other developer account

Note that the Apple requires bundle IDs to be globally unique. So if you have an app with bundle id "com.example.app" from a dev account, you can't re-use the same bundle ID in another dev account (even though the team id/prefix would be different).

Ensure that the new distribution certificate is in your keychain and the new provisioning profile on your disk.

1. Unzip the .ipa. This will usually unzip to `Payload/<app-name>.app/`
2. Export the entitlements.plist from the app