[Q] upgrade Flight-6 to Flight-7?

[Ken Hopper]

Hi, I have a brand new Flight 7 (6.06b3) ISO CD and I can't figure out 
how to upgrade my nice Fligt 6 (6.06b2) desktop. I tried adding the 
CDROM to Synaptic and it said "no module list found, not a Debian 
upgrade CDROM".  Anyone know how to get from Flight 6 to Flight 7 
without destroying (reinstalling) a whole new Ubuntu?
many thanks,
Ken (be gentle, I am a Ubuntu newbie)