Converting file formats without losing Rekordbox info?

Sorry if I'm not using the correct technical terms, I'm still quite new to this.

I had my first DJ gig recently, so I made sure to export everything properly through Rekordbox so there are no surprises when I connect it to the CDJ (XDJ-700). Unfortunately, I found our mid-set that the player does not support many of my files. I'm pretty sure those were the FLAC files.

So, looking towards my next gig, I plan to bulk convert all of my FLAC files to high quality MP3. Problem is, I have quite a few of them, and I don't want to manually replace them in my Rekordbox collection after creating the MP3 versions unless there is no other way.

What's the best way to go about this?