Never used one before.

What happens to the certificate if companion cannot go on trip? Is it burned?

Also, looking at using RUC on trip as well (MEM>ATL/DTW>HPN) usually get about 50% upgrade as GM (now PM - may hit DM by trip) to F (especially in & out of HPN)...would that be a good use of RUC since shorter legs are the ones (ATL and/or DTW) that are harder on complementary upgrades - or save RUC for longer trips....

Thanks!
FH