Question : Adding a sub-domain

My question is...

We changed are internal domain name from abc.com to efg.com.

our email address are  [email protected]
I set Exchange 2003 to accept mail under policies, for  @abc.com

But when I do pop3 it will only accept     [email protected]

How do I add a subdomain or fix this?

Answer : Adding a sub-domain

add it as UPN suffix from active directory domain and trusts
righ lick on the domain
then add the UPN suffix