If you have attached numbering to paragraph styles, you can certainly delete the numbering from each of the styles.

If you are trying to delete custom formats from the galleries at Home > Bullets, Home > Numbering and/or Home > Multilevel List, exit Word and delete the ListGal.dat file. You'll find ListGal.dat in your user profile path (to locate it, display hidden and system files in File Explorer).

As Charles said, an example would be helpful. :-)

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional