Both utility models and inventions can be modified voluntarily. General invention patents can be modified voluntarily when they request substantive examination and within 3 months from the date of receiving the notice that the application for a patent for invention has entered the substantive examination stage issued by the patent administration department of the State Council. For utility model, the application for utility model can be modified voluntarily within 2 months from the date of application. However, no matter whether it is a new type or an invention modification, it shall not exceed the scope recorded in the original specification and claims.
it's not possible to change the patent application document to "men only" for the "men only" you proposed. Although your modification narrows the scope of protection, your application document does not record "men only". Therefore, from the perspective of patent law, it is actually beyond the scope of the original application, so it will not be accepted by the examiner.