I’ve never prayed to a saint, but I have have asked the saints to pray for me.
(1 Corinthians 6:1-2; 1 Corinthians 16:1,15; 2 Corinthians 1:1; 2 Corinthians 13:13; Ephesians 1:1,15,18, etc.)
If you have asked them to pray for you then you have prayed to them. This is not to be confused with worship which is only directed to God.