I just tested this, and unfortunately I don't think it's possible to copy between different Prep Builder flows.
It's defo worth adding this to the Ideas section (Ideas ) as I know for sure developers use this community to check into what us as users are looking for!
I hope this helps!
Thank you for your replying. I got it.
Susumu, are you saying you were able to get Prep to copy between flows? I have been trying to do this and have been unsuccessful.