It can happen.
We know the story, but we don't think about it much (when we should). Saul was the number enemy against the Followers of Jesus. He thought they needed to be locked up or killed. Acts 8:3 says, "Saul began ravaging the church, entering house after house; and dragging off men and women, he would put them in prison."
He even went so far as to follow them to other towns. He was in a fury. He was on a mission. He hated these Believers.
But in an instant Jesus changed him. Jesus confronted Sault in a vision and Saul became Paul, one of the mightiest Believers ever.
Why do I remind you of this story?
Because of those people you have been praying for for a long time. Those people who need Jesus who have no desire for Him. God can change them in an instant. We don't know what is going on in their hearts. We don't know what God is saying to them. We don't know how God is speaking to them. Don't quit praying. Prayers are never useless. Prayers are never wasted.
Sometimes it takes years, decades, lifetimes to see people come to Jesus. And you might not see that one person come to Jesus. Maybe he or she will come to Jesus after you're gone. That's okay. Even if you aren't around your prayers still are. God is still answering. God is still aware. God doesn't give up.
Speak the word into their lives. Pray the word into their lives.
"So shall My word be which goes forth from My mouth; It shall not return to Me empty, Without accomplishing what I desire, And without succeeding in the matter for which I sent it." Isaiah 55:11
That is an amazing promise God has given us! Use it!