A domain name transfer is the process of changing the designated registrar of a domain name. For example, moving a domain to LCN, from a different registrar.
The domain name itself stays unchanged, as does details like the registered owner, registered address and other domain information. A common reason for moving a domain between registrars is to consolidate domain names with a registrar company you like. Perhaps you like the customer service or features a particular registrar (such as LCN) can provide.