Yes you can. It has to be done before Jun or Jul. Max 15,000 miles. Basic cost is $25 plus 1 cent per mile. It will take a week for the miles to be posted in the other person's M+ account. And, you have to request this through the web.
I was trying to upgrade a friend using NA confirmed upgrade. The phone agent suggested that it's better for me to do miles transfer since my friend only needs 4000 miles more. And I don't need to go to the airport for authorization.