Email delivery
Hello,Couple of questions for the gurus.

We have a domain on our server that uses a PHP script to send emails to another domain, not on our server. Planning on moving the second domain to our server as well, I set up the domain in WHM, but due to several issues the DNS was never modified at the registrar for the second domain.
As a result, all email sent from the first domain to the second is being delivered locally (to the second domain I set up on our server), instead of being delivered to the server that it is currently on. I did modify MX in DNS for the second domain to point to the other server, however locally it is apparently not resolving to the new server.
So, two questions:
1. How can I get all email that was delivered locally (to the yet-unused domain) to the server the second domain is currently hosted on?
2. How can I make our server resolve the appropriate address for the second domain instead of delivering mail sent locally to the local account for the second (un-transferred) domain?
Hope that makes sense - any help is highly appreciated!