Want to stop breast feeding

I know breast milk is best milk and all the nutritional value it gives the baby! Im just exhausted and tired, and hoesntly I don't enjoy breastfeeding. My baby is currently 4 months and I want to switch to formula. Has anyone done a switch like this and was the baby ok with the change. I give her one formula feed every night, since she was 2 weeks old.

Also, what is to be done about the breast engorgement ? Should I just gradually cut down on feeds? Or anything else can be done?