Just a question on rebuilding attraction, can it be done?

Say you have a thing with a girl, an amazingly strong connection, but due to things going on in her life she decides its better to be single. Lets also say that the 'break up' was emotional both sides and as time goes and while you're trying to be friends, her attraction for your fades.

Further down the line is it possible to rebuild the attraction you once had with each other? If so, how would you go about doing it? Or once it's gone, is that it?

Not saying I'm going to wait around for her and try to rekindle things with this girl, I'm more curious if this can happen or if others have done so and how did it go? I guess this could also be like getting yourself back out of the friend zone.