It may be difficult to correspond with the PTO via mail only. Often a discussion between an applicant and the examiner can help advance prosecution and identify patentable subject matter. 

When an interview could be helpful in advancing the prosecution, the PTO will allow interviews in the form of personal appointments, telephone conversations, video conferences or email.

The applicant or the applicant's power of attorney may be involved with these interviews. When a face-to-face interview is granted, it must be held on the Office premises unless authorization has been granted to hold it somewhere else. Normally, these face-to-face interviews will take place in the examiner's office, a conference room or the video conference center.

There are only certain times during the prosecution that interviews will be granted. An applicant will never be granted an interview before the first Office action has been sent out, unless that application is a continuing or subsequent application. However, after the first Office action has been sent out is a much different story.  Applicants may be granted interviews after any Office action. They are not generally granted after a Notice of Allowability has been mailed.

The PTO always has the last word when it comes to granting interviews.  The applicant may merely initiate a request for one.

If the interview is granted, the applicant or the patent practitioner will need to file an interview summary form which will be recorded in the application file. This form should include the relevant application particulars in addition to what exactly was discussed, whether an agreement was reached, the results of the interview and the examiner's signature.