As mentioned, what you heard is probably 그래요, which is very often used. 그래요 can mean two things: 1. That's right; It is so. It is a phrase of agreement coming from 그러해요. 2. Ok, go ahead (with what we talked about); Ok, do so then (like "permission granted"). It is a shortening of 그리해요 and 그렇게 해요. In an office setting, #2 usage is often heard, especially if someone ends a conversation with it or just say this one phrase after hearing a request or proposal.

그래요? If I have the right word, it basically means "that's right". I can't really think of another use for it. If you can't read hangul I would say my closest pronunciation to it would be "geuraeyo", but the g sound can sound more like a k sometimes.