Just be honest and respectful. Preferably over the phone/audio/video rather than an email. Also, be clear and to the point, so they know you're not just trying

Just be honest and respectful. Preferably over the phone/audio/video rather than an email. Also, be clear and to the point, so they know you're not just trying to get more money out of them. (If it's just about the money and they offer, it's a different dilemma).