Let's say a repo named cool-stuff is on github.
I have a fork of cool-stuff and I have submitted a PR associated with my fork of cool-stuff which is waiting to be merged.

Now, there is another independent fork of cool-stuff,say, even-cooler-stuff which works on new features to introduce to cool-stuff. I would like to contribute to the even-cooler-stuff repo but github won't let me since I already have a fork of cool-stuff.

Is there any way to do what I want like this or should I manually tell the author of even-cooler-stuff the changes I want to do?