Change Mailbox to Alias

[#1]

Hi all,
I set up an extra mailbox for someone who was doing some work for me (let's say the mailbox was called "Paul"). I'd now like any mail addressed to "Paul@domain.com" to be redirected to "John@domain.com".
If I was doing this from scratch, I'd just set up an alias called "Paul", but obviously I can't do this. I thought, however, that I should be able to set up a Redirect - but this doesn't work either (tells me that "The name Paul is already in use or is a reserved name. Please select another."
I also don't want to delete the mailbox because there is email on the server that isn't downloaded anywhere yet.
I could do it by setting up a Catch All, but don't really want to leave myself open to spam (and I'm not really expecting many emails to be sent to "Paul".
Any ideas? Thanks in advance for your help!
Stuart

[#2]

Will the following achieve what you want?
1. If mailbox 'John' doesn't exist create it,
2. move the mail in the 'Paul' mailbox to 'John'.
3. delete the 'Paul' mailbox and replace it with a redirect to 'John'.
David

[#3]

You could also set up a catchall first so that any mails to Paul which slip through before the change happens are caught. Then remove the catchall

[#4]

And now for a really stupid question - how would I move mail from one mailbox to another? I sometimes wonder about my intelligence levels!
I'm certainly glad that you guys are here!
Thanks,
Stuart

[#5]

cough 
I have no idea other than using the forward option which then means you need to edit all the emails afterwards

[#6]

That makes me feel a bit better!
Cheers,
Stuart

[#7]

You could set up both accounts using IMAP and then transfer the mails from one account to the other using drag and drop and a local mail client like Thunderbird?

[#8]

Using IMAP and Thunderbird is the way I move messages between mailboxes - I have multiple mailboxes displayed simultaneously. One can select multiple messages from the source Inbox, then right-click and select Move To (or Copy To) on the cascading menu leading to the desired mailbox.
I think one can probably do this with any mail client that supports IMAP and the ability to open multiple mailboxes simultaneously (which excludes webmail).
David