If you have domain based email set up with your current host, you may need to make arrangements to save any emails that you retrieve remotely (ie login to an email portal to send and receive).
If your emails are set up locally (on your computer) with POP3 settings, the emails will remain in the email program during a domain transfer or change to the name servers.
Once the emails have been recreated at the new registrar, the emails will be functional. In cases where the email address has been set up using IMAP settings, the emails will need to be saved prior to any changes to the domain settings.
Please contact the Support team with any questions.