I doubt any isolation exercise we choose to isolate a muscle truly does isolate. The body has an annoying habit of complicating things, and leg curls most ppl choose for hamstrings probably do hit the glutes a little. That said, your neighbor (woman?) will be better served doing any of the stuff mentioned above. Some gyms have machines that are aimed at glutes, but all gyms have what you need for squats, deadlifts and leg presses. Males/females tend to prioritize different bodyparts, beginners especially, you might see, or provoke, more discussion of this in the Woman's section here. For full disclosure, remind your neighbor of genetics too, some ppl are gonna have a relatively flat ass no matter what, while some were born with just the opposite.