PCT International Search and Preliminary Examination Guidelines
PART VIII CLERICAL AND ADMINISTRATIVE PROCEDURES
Chapter 22 Clerical and Administrative Procedures
Irregularities in the Mail Service
22.52 For the applicable procedure in case of delay or loss in the mail or in case of interruption in the mail service, reference is made to Rule 82. Rule 82 applies also if a delivery service is used to the extent that the International Searching Authority, the Authority specified for supplementary search, or the International Preliminary Examining Authority accepts evidence of the mailing of a document by a delivery service other than the postal authorities.