When others sell the products which are the same or similar to the patent/the utility model of an applicant, or an applicant receives a warning notice related to an infringement of the patent rights, the applicant should cope with those situations by sending a response via a content-certified mail. The warning notice related to the infringement or the response must be prepared sincerely by the person who has sufficient special knowledge of the patent laws so that the dispute can be settled as soon as possible.