Abbey National has told more than 2,000 staff they must reapply for their jobs as part of a big shake-up.
There could be redundancies, a spokeswoman said, but she added that these would be kept to a minimum.
As part of the restructuring Abbey National will bring back the title "branch manager", which it did away with four years ago.
All 743 branches will now get branch managers and there will be assistant managers at the 150 biggest sites.
But the bank will get rid of titles including local market manager, local sales manager and client manager.
The company said it would also be creating 450 new jobs to help customers with personal finance.
The revamp is part of Abbey National's attempt to restore its fortunes after making a loss of �984m in 2002.
The chief executive, Luqman Arnold, has warned that the bank faces "a long, hard, process" as it tries to get back on track.