changing registration from outside Canada
Nobody from Alberta replied , so let this Ontarian give it a shot.
You do not provide much detail as as to where you are and where you expect to get this registration change done.
Mind you, I have no experience with Alberta but the provincial reg. systems work fairly alike.
Do you live in Alberta and are away or are you from abroad and bought the bike sight unseen?
If it is anything like in Ontario you will have to go to the licensing office in person with the registration slip signed by the previous owner and then will have to provide proof of a safety inspection having been carried out, lien check been made.
Only if all this is done and after you pay the required fees will the ownership / registration be made out to your name .A selling contract is nice but means nothing to the license office, they recognise only the provincial registration forms.
I may be wrong , but I do not think it will be possible to get the documents without being personally there to sign them.