Most Helpful Girl
I agree with most people on this post in that it's all relative, annoyingly. Assuming this is a breakup, though from the phrasing it sounds like you'd want to regain some form of friendship with this person?
From experience all I know is space is so so important. My friend liked this girl for four years and it wasn't reciprocated. As soon as he went to uni and made a point to not chat to her for a bit he moved on in like a month. They're good friends still and they're both pretty happy. He just needed some time and distance.
Again, it's completely relative and depends on the length of time you were together and stuff, but if you want to help this person, my advice is space. (Though of course this is different to just ignoring them - let them know you're giving them space if you can.)
It'll all be cool :)