Final answer:
The 25th Amendment to the U.S. Constitution outlines the procedures for the vice-president becoming the acting President. The vice-president can assume this role if the president is unable to fulfill his duties, as stated in a written declaration sent to Congress. The vice-president then takes on the powers and duties of the office until the president can resume his duties or until Congress determines otherwise.
Step-by-step explanation:
In the United States, the procedures for the vice-president becoming the "acting President" are outlined in the 25th Amendment to the U.S. Constitution. According to this amendment, if the president is unable to discharge the powers and duties of his office, the vice-president can assume the role of acting president. This can happen when the vice-president, along with a majority of the principal officers of the executive departments, or another body as provided by Congress, sends a written declaration to the President pro tempore of the Senate and the Speaker of the House of Representatives stating that the president is unable to fulfill his duties. The vice-president takes on the powers and duties of the office as acting president until the president is able to resume his duties or until Congress determines that the president is unable to fulfill his duties.