[H] Upgrading from 10 to 10 Pro

[Thane Sherrington]

I have a client who ordered a computer with 10 and prior to delivery 
decided they want Pro.  I know I can upgrade through the store, but the 
store wants me sign in with a Microsoft Account. If I use the client's 
MS Account, then it wants to bill him.  Can I login to the store with my 
MS Account, purchase the upgrade and upgrade the computer, and then 
switch the computer to his MS Account, or am I going to end up with the 
license in my name rather than his?

T