Originally Posted by findark

My recent experience (and this has been debated in the award waitlist thread) is that the waitlist will be automatically converted to an upgrade standby list position ~10 minutes before checkin opens for the first departure on the segment(s) with the waitlist (using break-in-travel or ticket break, whichever is first).

The auto-add should assign you an SSR code based on the requested class - requesting P should have priority over PN, R, IN, and I. Note this is not "PR-1" status, and that in the case of a waitlisted IN award, it will not prioritize over GPUs.