How do I change the SMTP Relay on a PHP Form?

I have the same site on multiple servers. On the GoDaddy servers when the PHP form is submitted it errors out. GoDaddy Tech advises that when this form is on there servers I must change the SMTP Relay to a href="http://relay-hosting.secureserver.net/" rel="nofollow"http://relay-hosting.secureserver.net//a - Apparently anything not sent there from a GoDaddy PHP will fail. I've looked through the PHP form and didn't see anyplace to change that address - Any Advice?