To slim down do any type of cardio you like to do, at least 3 times a week, but also keep up your strength and do you normal strength training. You already got muscle under there, it's not going to make you look any fatter working the muscle, as the more muscle you build the more you burn fat with cardio, so it actually melts the fat away faster. Now one thing to note, there is no way to tell your body, eat the fat from my thigh first. It just doesn't understand, so when you burn fat, it's going to burn it from where ever it wants, but the good news is it will kind of do the merry-go-round thing, and take it from all different places in the body, but it can be awhile to really see it in both areas because of this.
It's kind of like tossing a handfull of pennies on the floor and letting a 3 year old run over and bring each back to you. They don't always pick them up from the same area ans work their way, further away. It's just sort of random, and what ever penny that happens to catch their eye next. This is about the same techique your body uses to burn fat.
Kit