Yeah, it definitely needs to be done tomrrow, if it's going to happen for you. You know it won't happen on the day of departure. There's not much that can make it happen by that time.

For something like this, I'd probably be calling skymiles and asking to be transferred to the SLC cust. serv. center. I've had the best luck with them dealing with the most adverse situations. I may be wrong, but they seem to be more well trained/empowered than the ticket agent you'll encounter when you get to the airport tomorrow, but that doesn't mean to not try there, too.

Good luck!