We did this several years back. If you have a good relationship established with your accounts it is not too bad. We just explained that we provide them with a quality service and that we were not charging enough to cover the cost of providing that service. We told them that we are diligent in doing all of the work that many billers and billing services push aside and that we make sure they collect everything that they are entitled to. We have quite a few accounts that we don't do the patient billing portion and on them we explained that the increasing copays and patient responsibilities was a part as well. That was many years back when we were charging a % to many clients. Now we have mostly flat fee clients and for them we just say that we've analyzed the account and taken a look at many things, amount of time spent on the account, volume of patients they see, types of services billed (some require more work), types of insurance billed, if provider is in network or out, etc and that we need to raise their fee effective May 1st (or whatever). We try to give them at least 30 days, usually more, and then have them sign a new contract.