Petry (15% retain) for Klingberg + 2nd.
Both player asked for a trade. Petry has 3 more years, Alot of team would sign him for 5.3M / 3 if he was UFA. Klingberg is UFA, Dallas will have a hard time flipping him for a current player to help them contend, Petry gives them that.
Dallas gets a legit top 4, arguably top 2 if he doesn't have to be THE guy, wich he wouldn't.
Montreal gets a 2nd round pick, have 1 month and a half to to try and sign Klingberg at a decent cap hit. If he doesn't want to play here ( wich i would understand considering his age) you flip him at the deadline for prospect and picks.
PS: I know Petry is playing terrible right now, but we got to take things into perspective. He doesn't want to be here, his familly isn't here anymore, the covid situation in canada and the whole team is currentely collapsing. I think it's circonstantial, Petry isn't a different player than he was 6 month ago.