Again, click the "CHECK IN" link on the front-page of
www.delta.com (between FLIGHT STATUS and VACATIONS) fill in your conf number and SLC as the FROM AIRPORT (assuming that's your turn point). You should be able to check-in for the return segments before you depart on your MR using that trick.
I've never noticed that! Sometimes you search everywhere and can't find what you are looking for. I'm doing a same day return tomorrow. I'll try it. Thanks, LBJ