Office Action calls for a legal writing.
When there is problem with your trademark application, the Office will issue an OA. There could be multiple instances of OA per application while many trademarks get registered without any.
Sometimes, a simple change to your application can fix the problem, so the only thing you need to is agreeing with the change. But often you must rebut the rejection with legal arguments. This provides you of an opportunity to clarify and strengthen your application (and the trademark), but a wrong response could render the trademark unenforceable or nominal.
You must understand the reason for rejection clearly and respond to every issue to the full extent. You might find it helpful to review similar OAs and corresponding responses from another applicants on the TSDR (Trademark Status & Document Retrieval), which is open to the public and FREE. Although you can borrow their legal argument and logic, you must apply them to your facts.
Consult an attorney regarding an OA - Make It Happen