Hi Chase, currently to do an untrim all the edges of the face's trim boundary need to be selected and not be joined to another surface.

In a case like you have here for this face:



You'll need to use Edit > Separate on that face so it doesn't have any joined edges, and then you will need to select the full trim boundary like this (you can select 1 edge and then use Ctrl+A for a shortcut):



Then you'll be able to hit Delete to do an untrim. Also another shortcut is to run ShrinkTrimmedSrf on it before doing the untrim, so you won't have to retrim the ends.

- Michael

Worked perfectly! And makes a lot of sense; I have to select the entire trimmed edge (which is just the circle in the case of the holes ones that are right in the middle of a single surface.

Thank you, Michael!