After much Googling, I think I've confused myself concerning DNS-related things.
For a client, I am moving a site from Network Solutions to GoDaddy, both the domain registration and the hosting account. I have replicated the site on the new hosting account successfully and am at the point where I need to initiate the transfer and then change the nameservers once that completes. That part I think I'm good on.
Meanwhile, they have email hosted at Rackspace (which I've never used before) and I'm wondering if any settings on Rackspace will need to be changed in this situation or if I only need to change settings on the new domain/hosting account?
Also, in either case, will there be a period of email outage/delay or does a 3rd party service like Rackspace solve that problem (assuming both the old and new hosting accounts keep operating)?
Thanks in advance.