Hi Catherine-
The answer depends on if you have your own server or if you are working with a hosted server.
If you have your own server, all you need to do is change some definitions in the DB.
If you are working with on a hosted server, you will need to switch out the phonedial swf after publication. Let me know and I will post the fix. I'd do it right now, but I am not on my desktop machine.
P.S.
NMC will be making this change to their hosted servers once they officially launch their services.
Best,
Scott