You keep your date of hire for vacation accrual and pass travel. Then you are the most senior pilot in your new-hire training class.....you get a new date of hire for pilot bidding and cockpit jumpseating.....you also as a company transfer get (3) guarantee interviews, and different mins requried....and the vacation accrual at 11 years of company seniority would be nice to keep, along with the pass travel, and option to interview at different times.
You also maintain recall rights to your old job (formula used based on your time in that position) would be about 5 years for me, so if the company sustained another 9-11 type event, and laid off pilots, I have the right to assume my previous position at no loss in seniority or pay benefits.......