 Do you know the 25th Amendment has only been invoked six times? Most notably, Section 3 of the 25th Amendment was invoked when Ronald Reagan and George W. Bush underwent minor medical procedures. Both Reagan and Bush transmitted letters to Congress, delegating authority to the Vice President for several hours, but usually only during colonoscopies or surgery. Section 4. Whenever the Vice President and a majority of either of the principal officers of the executive departments are such, so the Cabinet can invoke the 25th Amendment.