No, priest are for keeping the doctrine and serving as bridges between the faithful and their god(s). Theologians are the ones who update (or uphold) the church system of belief.
Only in the same sense that clothing has a mechanism for change because fashion exists. Theologians have no way of contacting their gods(s) or even knowing whether they exist. Their opinions are not based on evidence.
Sure they are, but in an evolutionary sense not in a scientific sense. Countless theologians have said countless things and most have gone in to the dustbin of history. But the things that resonated or were useful have remained.
Religion is the result of evolutionary processes and like all evolutionary processes it changes slowly and is not perfect. D.S. Wilson's Darwin's Cathedral is the go-to book for this argument and contains a beautiful section that goes like this:
We look at a bird's wing and marvel that it is so wonderfully adapted for flying. But we do not scorn birds for not being able to fly faster than the speed of sound. Their wings never required that to be successful in their evolutionary niches. Why do we look at religion which is also a marvel of adaptation for helping humans live together and get mad at it that it has not brought about world peace? World peace or perfection were never required for them to be successful in their evolutionary niches.
The issue with trying to make an argument that religion has no mechanism for change is that religions have and continue to change. So whether the mechanism is a priest, a turtle's dream, or if it's because of evidence is largely irrelevant. Religion does change.