This is one event, told four separate ways but included in all four gospels to fulfill Jesus prophesy about her. Luke’s account, for whatever reason, is simply not in chronological order.
If we allow all four of theses stories to harmonize, watch what happens… there is something really special. In Luke’s account (LK 7:40), Jesus begins by telling Simon the Pharisee, at who’s home this is occurring, a parable about gratitude. Why this story? Why make this point to Simon the Pharisee unless Simon should have had a far greater degree of gratitude for something. The point of the parable is that the person who had been forgiven much, would love more. Jesus is not talking about the woman, he is talking about Simon!
Simon the Pharisee was holding a dinner in Jesus honor. He was indeed grateful for something Jesus had done for him but not grateful enough to understand that his need for Jesus was just as great as this sinful woman. He is still blind. He could not see that he too had been “forgiven much.”
If we allow these events to harmonize, and take a look at the larger picture, we see Simon the Pharisee not only as the Pharisee, but as Simon the Leper… the healed Leper, for a Leper could not host a banquet (or even a snack) if he had not been healed! He would have been forbidden such close contact with other people.
This is one account fulfilled in the four Gospels.
By the way, the woman is actually Mary, the sister of Lazarus. (John 11:2)