How to chenge the defualt repo the pull request is directed to when creating a new pull request

[luca_confalonieri]

Hi all,
Not sure how to explain it. I'll do my best.
I have a repo 2 that was forked from repo 1.
Every time I do work on a new branch on repo 2 and crate a pull request, this is directed to the master branch on repo 1 whereas I need it to be repo 2.
We need to change it manually every time, which is fine, but a bit annoying and sometimes people forget to do so.

Is there a way, like in settings, to set the default repo to which the pull request is directed to?