modifying or deleting old saved custom format and appearance attributes

hi there,

is there any way to modify or delete old saved custom format and appearance attributes that one creates while doing the editing?

modifications and corrections keep on happening all the time as one progresses in one's job. but i am not finding a way to modify or delete to create a new one. this makes the list very long and ardous to choose in a big list.

as the new settings happen old become obsolete so then they should be allowed to delete.

thanks in advance for any help on this.