21FEB LHR-IAD-BOS - no problems; went smoothly. Even into the lounge without my card in LHR!
23FEB BOS-EWR-LHR - no problems with a reschedule: Inbound flight was delayed causing a missed connection on the original 7:15pm flight to London. UC agents rebooked me without problems on the 10pm.
Additionally, miles posted for the FEB21 flights already!