Originally Posted by
Harry IAH
Now I should be watching for availability in P-R fares, with R or RN meaning the upgrade should be processed?
Correct. Generally, your upgrade will clear automatically if R becomes nonzero. This, however, has been observed not to always work properly, and if you observe R>0 you can call and ask for your upgrade to be cleared manually.
We have a generally poor understanding what, exactly, RN is, but R=RN >99% of the time, so it's generally moot.