Question on transfer domain

[mdbusa]

Hello

I want to transfer one of my domains to go daddy. I signed up at go daddy paid the fee blah blahblah but was told that my my domain was locked by its registrar.

Ok so i get the registrar to unlock the domain. and try to reinitiate the transfer but it still fails.

I dont get it. I am missing something here. How does my existing registrar know to transfer the domain to go daddy? I never gave godaddy any password or anything to that domian.

Can somone explain how this works?

Thanks