Is there a way to delete a single user catalogue or do they have to be all deleted to replace one?

I have several 'catalogues' or lists in my User file each starting with a different set of letters, e.g. FG for Flat Galaxies, CS for Carbon Stars, etc. To delete any set, I open the saved txt file on my laptop and delete what I want, Save, then upload again to the Argo Navis.