God wants everyone to be saved but people have free will.

(Matthew 7:13-14 NIV) "Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it. {14} But small is the gate and narrow the road that leads to life, and only a few find it.

If you're praying for someone's salvation it means that God has already put a Christian in their life.

You can pray that God will help the person understand the gospel when they hear it.

Otherwise when you pray for the salvation of someone you're asking God to change their free will so they can accept Christ out their own free will. It's a contradiction that doesn't make any sense.