I'm pretty sure it is I just want to confirm. I've spent some time reading the rules regarding SDC on Delta.

I have a award flight: TPA-LAX-SFO-HNL booked in First (R) and want to do a SDC to TPA-ATL-HNL to take advantage of the better plane and less stops.

The TPA-ATL-HNL is also First (RS) class and based on Delta's SDC policy for first class tickets "If you have a premium cabin fare, -- including Delta One™, First and Business Class -- you may make a same-day confirmed change as long as a seat is available in the premium cabin"

This should be no problem right? I think the only hangup I had was what first (RS) was but I guess its irrelevant because its the same cabin, just a different fare type.