Over watch cardback

Hi,

My sister bought overwatch origins edition on a physical game store but she wants to put it im her account. Is there anyway to get the overwatch cardback without putting the game in my battle.net account?

Please help.

I didn't find the right solution from the Internet.

References
www.hearthpwn.com/forums/hearthstone-general/general-discussion/190947-overwatch-cardback
IoT Application Video

Thanks