MPEP App. T, Rule 46
The time limit referred to in Article 19 shall be two months from the date of transmittal of the international search report to the International Bureau and to the applicant by the International Searching Authority or 16 months from the priority date, whichever time limit expires later, provided that any amendment made under Article 19 which is received by the International Bureau after the expiration of the applicable time limit shall be considered to have been received by that Bureau on the last day of that time limit if it reaches it before the technical preparations for international publication have been completed.
Amendments made under Article 19 shall be filed directly with the International Bureau.
If the international application has been filed in a language other than the language in which it is published, any amendment made under Article 19 shall be in the language of publication.
The applicant shall be required to submit a replacement sheet for every sheet of the claims which, on account of an amendment or amendments under Article 19, differs from the sheet originally filed. The letter accompanying the replacement sheets shall draw attention to the differences between the replaced sheets and the replacement sheets. To the extent that any amendment results in the cancellation of an entire sheet, that amendment shall be communicated in a letter.