I have a client that is part of a city sponsored 457b plan. He is a firefighter and part of the firefighter's union. My question is can the union break off and set up their own plan with another vendor? (assuming all of the firefighter's agree). Do they need to get approval from the city to do this?

see Revenue Ruling 2004-57, here: ftp://ftp.irs.gov/pub/irs-drop/rr-04-57.pdf