Hello, i only would like to know before i do something wrong and then my file stucture could be damaged.

Situation is as so:
- USB-Stick - Fat32
- about 450 Folders (CD) with audio files, mostly .flac
- Some folders contains some .mp3 and some .m4a

I would like to convert the .mp3 and .m4a to .flac

Is it possible to overwrite the existing files? I don't like to have the new converted files with the older .mp3 and .m4a beside

Or, output the converted files to a new directory, but how to put them back to the stick and than delete the older .mp3 and .m4a

How to? What must be the best way to have all selected files as .flac and kep their place in the filestructure ...

Thank a lot