I want to buy my sister's leased car. What is the process?

Discuss with the dealership that she leased it from.

Pretty easy, I assume that she satisfied the lease and made all the payments? Go to the dealership with her where she leased the car and tell them that you want to purchase it in your name. VERY IMPORTANT, there's a hard number that they offered your sister to buy out the car.... DON'T let them tell you that this would increase if you purchased it.... If they do, you have two options, have your sister purchase it for the agreed price and buy it from her or, WALK AWAY....

Good morning Bob, I assume that you like Toyota's.?