I understand that agent doesn't have a law degree, but can she represent the inventor? I am writing my patent application by myself but want a professional to look it over and make corrections, especially claims. Probably lawyer's fees are too high for me and patent agent should be able to do the job. But all I can find are law offices.
To the United States Patent and Trademark Office (USPTO, as I'm sure you know it) in the context of patents (that is, not for trademarks), a registered patent agent is pretty well the same as a patent attorney. They can both file the paperwork, and there aren't any patent skills implicit to someone who's gone to law school, let alone passed the bar, that a well-taught agent wouldn't also have.
In other words, an agent will be able to do what you're looking for.
Attorneys become necessary when you want to do some other things, like write an assignment agreement or, interestingly, file a trademark. But for just doing the filing or review of an application, you don't need someone with a law degree.
That said, I wouldn't jump so quickly to the conclusion that a lawyer's fees will be higher than those of an agent (they often are, but be careful assuming it), but either should suffice. I'm sure you've done your research, but I just want to say that to be extra clear. Because "esquire" status doesn't allow for any more behaviors in this context, it's quite reasonable for a patent agent to charge similar rates to an attorney.
You can locate patent agent using USPTO register:- link