I am planning to request an override via e-mail for a class which is taught by two professors; one of them holds a PhD, while the other hold a master's; I have never met either of them. Usually my first line would be something along the lines of:
"Hello Dr. X, Dr. Y"
However, I feel like if I say
"Hello Dr. X, Mr. Y"
it would seem a little weird. I don't want to be over the top formal, but I still want to be polite. I've thought of using "Pro. X, Prof Y" but I'm not sure. How should I address them?
My location is the U.S.