Hi Karen,
You just need to edit the Account information.
In OE, click File>Work Offline.
Click Tools>Accounts>Mail tab.
Highlight the Account you want to change and click the Properties button.
On the General tab, change the user information to reflect the new address and click Apply.
On the Server tab, change the account name to reflect the new e-mail address and change the password to the the new one.
If the new address is thru the same ISP, the server settings can be left as is.
Click Apply and OK.
Click File>Work Offline to remove the check mark.
Restart OE and the new address should be set up in the Identity.
If you want to keep and use the old E-mail address, just set up the new address as a New Account in the Identity, rather than editing it.
Tools>Accounts>Mail tab>New.
You can use Message Rules to direct the mail from each account into separate folders.
T.