Who brought the subject up? I believe if the other person brings the subject up, you actually have a duty to either share the Gospel “Good News” or your own Godly view of the world. Be sure you quote Bible verses and truths correctly.
You must give the other person their say, even when you know it is opposite of God‘s Word. It is polite, and they might listen to you better if you treat them kindly which is commanded and shows your obedience.
Know when enough is enough and have a plan in mind of how to escape before anyone is actually angry. Once a person has built up too much steam, they may decide to never talk to you in a personal way again.
Always show God’s love by using respect for where the other person has come from, or walked. You have no idea how they came to think what they think. Will you be the instrument that God will use to spread the gospel?