What changes in prayer is us. We can use them properly for positive ends and they will help us to perfect ourselves and the world around us. This is a two-fold mistake. First, G-d is Infinite. He has the capacity to have an ongoing individual relationship with every human being on this planet.
Prayer does that.
Every prayer puts one in touch with the Almighty. For a very holy individual, prayer might be sufficient. However, the Torah prescribes that while we must pray, we must make every effort in an intelligent manner to succeed. Please pray for Shmuel ben Fraida. He is having major spinal surgery to counter a life-threatening disease.