Oh, you wanted something really specific.
Darryl Sittler waived his no-trade clause to be traded to Philadelphia after a protracted battle with Leafs management, which saw Lanny McDonald shipped out to alienate Sittler. Sittler finally relented on the condition he be moved to either Philadelphia or Minnesota in 1982 Not the same CBA or era and Sittler is technically from Kitchener, but between Leafs core dismantling, long time Ontario born star, franchise change in direction vibes it's close enough.
Other more modern examples of guys who did the honorable thing might be Marc-Andre Fleury who waived his no move for the Vegas expansion, and Ryan McDonagh who waived to leave Tampa a few days after winning their back to back cup.
Again I'm just looking for historical examples I'm not saying to necessarily do anything about Mitch or Tavares today or tomorrow but with their contracts running down, if things don't go well. Some guys choose to leave willingly.