Executive Order 5463—Amendment to the Instructions to Diplomatic Officers
Chapter XVIII of the Instructions to Diplomatic Officers of the United States, entitled "Form of Correspondence with the Department," is hereby cancelled and the following substituted therefor:
FORM OF CORRESPONDENCE WITH THE DEPARTMENT
XVIII-1. Form and transmission of correspondence
The form of correspondence and the manner of its transmission will be governed by the rules on the subject established by the Department of State from time to time.
The White House,
October 15, 1930.
Herbert Hoover, Executive Order 5463—Amendment to the Instructions to Diplomatic Officers Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/361092