Like Jay said, you can't change bone, bit the bigger giveaway is the fat distribution there.
From personal experience, even at my skinniest, I had big hips. Problem is that with fat distribution, anything you do shed there is still the go to for new fat. Working out may help a bit though and can never hurt. I just know from personal experience that nothing I did worked too well, so I always disguised them with longer tees and overshirts. I never dared tuck a shirt in. But now I'm finding that the fat is dropping and staying off!! T makes a huge difference, but you still have to burn the fat off, it can't just migrate.
Longer tees, polos and overshirts help hide bigger hips. Try to avoid anything too fitted. There's also a very thin line between too baggy and too tight with big hips. It's crazy. The best way to deal with it, I found, is try on pants in store with a longer top and keep changing sizes until you find what works. It makes shopping a pain in the ass but it's worth it in my opinion.