An Official PCT Gazette Notice of 21-January-2010 identifies changes to the PCT regulations affecting applicant requirements when making amendments. The changes involve rules 46.5, 66.8, and 70.2 (c-bis).
The Gazette Notice states that the amendments to the PCT regulations provide for "(ii) the obligation for applicants, when making amendments to the description, claims or drawings, to indicate the basis for those amendments in the application as filed (PCT Rules 46.5 and 66.8, and new PCT Rule 70.2(c-bis))."
Thus, when amending PCT patent application (e.g., under PCT Article 34), Applicants should identify passages from the patent specification that support each amendment. For example, when amending claims, Applicants may provide a chart including each amended claim element and a citation to portions of the specification that support the amendment.