I have a question about this waitlist process. I've read a lot of threads, but still am not sure I understand the bit about checking R and calling in if I see space. I requested upgrades ($$ and miles) on an international flight next month. Of the four segments on that trip, two have cleared the waitlist; I'm waitlisted for the other two (one domestic, one transatlantic). So if I monitor the availability of R (currently at 0 on these flights), and see that R becomes available, and I haven't been cleared off the waitlist, and if I call in --- would an agent then upgrade me? or tell me that I'm still on the waitlist? or does it depend on the agent? And does it matter what fare I'm booked in? Does status?

(Is there an overview/wiki on all this upgrading?)