how to get rid of Hollow Audio Sound in FCP?

How do I get rid of the Hollow Audio sound of the recorded voice in FCP?
It was recorded in a room that had no sound protection so you hear an echo sound when the talent speaks...

It's very difficult if you're talking about room reverb. This really needs to be checked at the time of recording.

If the issue is so "tight" that it phase cancellation issues you could try reshaping the sound with EQ and maybe even a little reverb of your own.

If it's caused by phase difference between recorded two channels, that's a different story. Then you can start by killing one channel and checking to see if it sounds better.