This just happened to me over the weekend. My Thursday flight to Costa Rica put me past the PM threshold. Miles showed up on Friday, and my status changed Saturday. I was happy to learn that they process status adjustments over weekends because my return flight was yesterday (Tuesday). I was upgraded out of SJO and ATL. The SJO - ATL upgrade was confirmed on Friday before my status change (and interestingly >3 days out although I was officially still GM at the time), and I attribute my ATL - SLC upgrade to having PM status which kept me ahead of the 35 folks left on the waitlist at the gate.