Two recent examples via e-mail.
1) I was on a revenue PNR - booked family on AP with IKK, called regular SE line to link PNRs and move family to be with me in preferred seating - first time no issue, second trip wanted to the same and agent was insisting on a fee (maybe true but I said in the past it's been waived) - couldn't get it done so I just emailed concierge and no problem
2) Booked TATL in PE, saw P space available to upgrade, R was 0, eup tool waitlisted me, sent an email and upgrade processed