You submit the UPM for one profile for that PM. In the explanation box on the form, if desired, you can state there are no sources and you want to add sources. You also have an option to open all ancestors and descendants of the profile you are submitting it for. The Admin person, even without the additional note, may orphan all profiles of that member.
I have sent the form in for members inactive for a year. It depends on what you are trying to do, but it also depends on how active that member was, or has been, whether all profiles are orphaned or not. When we have profiles with no dates, it is especially problematic because then we get duplicates. With inactive members and locked profiles, we need admin to do the merges also.