In the past you started in reservations or check-in and got promoted to the ticket desk.A great deal of expertise and experience was required and the airline provided the necessary training.
However this job is gradually disappearing and paper tickets will disappear soon,replaced by e-tickets.I understand there are no dedicated ticket desks as such in Terminal 5.
I get the impression airlines want customer service staff to be jacks of all trades.This is all very well,but when any disruption occurs enormous queues build up since the expertise has gone.