To answer my own question as I have changed it out successfully. There are 4 locking tabs on the backside of the assy. 2 on top and 2 on the bottom. I could not gain access to the top 2 so I reached the bottom 2 by reaching up from beneath, unlocked the tabs and pushed out on the assy. I pulled the bottom of the assembly out far enough to cut the plastic with a hacksaw enough to break the assy in half to remove it. I fit the rubber seal around the fuel filler tube as I put the new one in