@Anonymousby reset you mean to the original color? Let me understand so I can help you
- have you allready tried to change one of those colors you don't want?
- are you selecting the Color Scheme Entry you want to delete?
- have you tried all three?
Considered you've tried, looking at the image you sent, by the Color Fill Legend of your view behind it seems that Ensuit is the only Department you have assigned to the room(s) you have in the model. That's because from the Color Scheme window you can see all three department entries are checked (Ensuit, Entry and Toilet). If you'd had any room assigned to Entry or Toilet departments it would show on the Color Fill Legend.
Probably you are not geting to delete Ensuit because it is assigned to the department field of at least one room of the model. As I believe, the other two entries (entry and toilet) are not in use and should delete icon should get red if you select any of its fields.
If nothing of this works, try creating a new Color Scheme. Not editing this one you are trying to but creating a new one and adding the department names you want to color.
Hope it helps.