When I say:
cite to someone as an authority
Does it mean
1. quoting to someone who is an authority
2. using a quote from someone whom is an authority
I am confused about the use of "AS"
I am talking to you about this as friend.
Could anyone please explain?
It means that you understand that this person is an authority and that you are asserting that this person is an authority. It could mean, as well, that you recognize that it's universally understood and agreed that this person is an authority.
The next sentence is the same. It means that you are talking to someone as a friend, not as any other kind of person, such as an authority. Saying "as a friend" means that you believe the person is a friend.