What's involved in rehab for sleeping pill dependency?

I just read something about a certain celebrity going into rehab for a dependency on sleeping pills. I've had chronic insomnia for over twelve years, and every now and then I've had Ambien prescribed to me, usually for just a two week period. More recently, my new doc has written me a script for 15 pills per month, and I take them every other day. On the nights I don't, I take a double dose of Klonopin, which I've been on continuously at a low dose for six years. On those nights, I rarely get any sleep. But I don't get great sleep with the Ambien, either (I'm hypervigilant due to PTSD). Obviously, people who take sleeping pills regularly do so because they can't sleep naturally and normally. So, how would rehab work?