There should be feature built in that if your duos partner leaves/ disconnects etc that you can then start to control their board.
I was having a really good match with someone and we built an amazing deck for each of us, their connection must’ve dropped though and they disappeared mid passing multiple cards.
Blizz flagged they’d left so it was just me left to concede as no chance winning without a team member - I reckon I could’ve finished the game if I had control of their deck though, we need this feature built in please.
P.S - I thought I already posted this but it seems to have disappeared - sorry if it repeats.