Canonically, a Dragonmarked creature will keep their mark even if they’re reincarnated, but can’t pass it to their offspring in their new form.
— Keith Baker (@HellcowKeith) October 4, 2019
Beyond canon, you can do whatever you want. In the Dreaming Dark novel, there’s a daelkyr experiment that involves transferring dragonmarks, though it ultimately ends up creating an aberrant mark.
— Keith Baker (@HellcowKeith) October 4, 2019
