Transfering a domain from one registrar (IE reseller) to another can be a pain, but yes you can - it normally involves a fee and manual actions from the registrars.
As long as the new registrar supports the TLD. A few Geo-TLDs can only be resold/managed by some registrars.
The easiest thing to do is to point the domain at ClouDNS nameservers.
Make sure you are happy with ClouDNS (I’ve never had issues with them) etc before committing