Artikel 39

1. To become effective, proposals submitted to Congress relating to this Convention must be approved by a majority of the member countries present and voting which have the right to vote. At least half of the member countries represented at Congress and having the right to vote shall be present at the time of voting.
2. To become effective, proposals relating to the Regulations must be approved by a majority of the members of the Postal Operations Council having the right to vote.
3. To become effective, proposals introduced between Congresses relating to this Convention and to its Final Protocol must obtain:
3.1 two thirds of the votes, at least one half of the member countries of the Union which have the right to vote having taken part in the vote, if they involve amendments;
3.2 a majority of the votes if they involve interpretation of the provisions.
4. Any member country may, no later than ninety days from the date of notification of an amendment adopted under 3.1, propose a reservation to that same amendment, subject by analogy to the same approval conditions as set out under 3.1 and the relevant provisions of article 40.