Hello all, its been a while, just getting around to updating my profile. I did a search on here but I am still 100% as to how system wide and regional upgrades work. I hit the 100k mark this year on CO.

I am flying to London and Bombay next year and wanted to use my SWU to get into BF. Can I just buy a coach ticket in the listed fares and instantly upgrade if there is a seat available? Do I get wait listed and if I don't clear I have to sit in a coach seat for 14 hours? Any help would be appreciated! Thanks!