You just have to phone round to local home health agencies, explain what you need, and see what they say. Start with small, locally-owned independent agencies, as you'll probably have better luck there. It can be a lot more difficult to get a corporate-run HHA to agree to let you shadow a PT. All the ones I phoned around here said it wasn't possible cos it violates their privacy policies. But the locally-owned HHA just had me sign a form saying that I understand I'm not allowed to talk about the patients to anyone.