Echo

Sorry to be the bearer of bad news, but I'm afraid you won't be able to do this satisfactorily. The sound you want to remove is at the same frequencies as the sound you want to keep, so differentiation simply isn't possible. And also, it's coloured the direct sound, so even if you use one of the reverb removers it will still sound substantially 'wrong' (and they don't work very well anyway).

This is the reason that people use lapel mics, or record in acoustically treated environments;  good fixes for this problem simply don't exist, and once you've learned this, you will go out of your way to avoid environments where it happens - or just live with it. Whatever you do, don't even attempt to use a camera-mounted mic - that's likely to produce the biggest disaster of the lot!