How can an Xcode Share Extension connected to one Parent target be disconnected and associated with another?

I have inherited a legacy Swift 3 app that features a Share Extension. The client would like to roll out both a production and a testing version of the app with each release: the same app but each having a different api url. I've been using this tutorial to create new targets with new bundle ids, but having duplicated the Share Extension target, it is still connected to the original App target, and throws the following error:

Embedded binary's bundle identifier is not prefixed with the parent app's bundle identifier.

I can't work out how to disconnect it from the original and connect it to the duplicate.

Can someone tell me how please?

Thanks for reading.

ps: the original question and text of this post were different, meaning the comments immediately below may not make much sense.

from How can an Xcode Share Extension connected to one Parent target be disconnected and associated with another?