Transferring Domain into Network Solutions (minimal downtime)

Hi everyone,

I need to transfer a domain from (A) into Network Solutions. This domain facilitates e-mail and web hosting.

Do you know if the name servers are hosted externally from the current registrar, if there will be downtime?

I want to know the best way for minimal downtime. I spoke with Network Solutions who said you need to set everything up again but I wasn’t convinced.

Do you know if when the transfer takes place the name servers will remain as they are and all related DNS records will remain in effect?

Kind Regards,
Travis