Will Falconer, DVM Moderator
An apartment complex?! Elle, unless the manager of said complex is an immunologist, he is asking you to potentially damage your animal for no good reason. It sounds like you need someone else to write a letter for you. Ideally, that'd be a sympathetic holistic vet in California, but I'm not sure any are brave enough. I'd do some "shopping" either by phone or internet/email and see my Resources page for both holistic vets and homeopathic vets.
I've done this for my clients many times and it's always worked. There's no "law" involved for an apartment, so it should be simple. (Well, I say that, but California may be vaccine-crazy enough to have one, so I hope I'm right).