Switching POP servers without switching names

[Joe DeBattista]

Hi,
   We have a machine where users pick up their email.  Call it
"machinea.x.y" and we will soon be moving QPOPPER to "machineb.x.y". I'd
like to avoid having to tell my 13000+ users that they need to change
their POP address.  machinea will still exist, so I can't just add
machinea as a CNAME to machineb in the DNS.

Any ideas?

                                 Joe DeBattista
                                 UCSF, ITS
                      INTERNET:  [EMAIL PROTECTED]