In my last promo game to gold, the enemy mid laner counter picked my Kassadin by picking Lucian. Thankfully, Jayce, our top laner, accepted to lane swap so I could go top lane vs Rumble. Had he not lane swapped, I would have got zoned and been irrelevant for most of the game. Instead, I was able to farm safely and get fed off Rumble and roams, ultimately winning the game.
Moral of the story : Don't be afraid to ask your top/mid laner to lane swap if you know beforehand that the matchup is unbearable/shitty. Again, shout out to the Jayce that literally made us win by biting the bullet for me. Thanks mate!