58 (e) advising the President. (4) Subject to this Constitution, the President may conclude or execute conventions, treaties and agreements with foreign states and governments and international organisations. (5) A decision by the President must be in writing if it is taken in terms of legislation. (6) In the exercise of his or her executive functions, the President must act on the advice of the Cabinet, except in respect of— (a) the appointment or removal of Ministers and Deputy Ministers; (b) the assignment or re-assignment of functions to Vice-Presidents, Ministers and Deputy Ministers, and the cancellation of any such assignment or re-assignment; (c) the appointment of persons to offices and posts in terms of this Constitution, or the removal of persons from such offices and posts, where the President is required to do so on the advice of some other person or authority. 5.24 War and peace The President has power to declare war and make peace, but a declaration of war or peace must be revoked unless it is approved by a resolution passed within seven sitting days of the declaration by a joint sitting of the Senate and the National Assembly. 5.25 Power of mercy (1) The President, after consultation with the Cabinet, may exercise the power of mercy, that is to say, may— (a) grant a pardon to any person concerned in or convicted of an offence against any law; (b) grant a respite from the execution of a sentence for any offence for an indefinite or specified period; (c) substitute a less severe punishment for that imposed for any offence; or (d) suspend for a specified period or remit the whole or part of a sentence for any offence or any forfeiture imposed in respect of any offence; and may impose conditions on any such pardon, respite, substitution or suspension. (2) Where a person who is resident in Zimbabwe has been convicted in another country of an offence against a law in force in that country, the President may declare that the conviction is not to be regarded as a conviction for the purposes of this Constitution or any other law in force in Zimbabwe. (3) The grant of a pardon or respite from execution of sentence or the substitution or suspension of a sentence must be published in the Gazette. 5.26 States of public emergency (1) The President may by proclamation in the Gazette declare that a state of public emergency exists in the whole or any part of Zimbabwe. (2) A declaration of a state of public emergency ceases to have effect after fourteen days beginning with the day of publication of the proclamation in the Gazette unless, before the end