18 CAP. 172 Immigration [Rev. 2010 (3) A provisional entry permit shall remain in force for the period of time specified therein, but if no period is specified it shall remain in force until it is revoked by an immigration officer and shall continue in force thereafter for three months after the date on which notice of its revocation is served on the person to whom the permit was issued, or is published in the Gazette, whichever date is the earlier, and shall then expire. Transitional provisions regarding re-entry. 21. Notwithstanding section 19, any person, other than a prohibited immigrant, who would but for the repeal of the former immigration law, have been entitled to re-enter Kenya by virtue of the grant of a resident’s certificate or of the issue of a re-entry pass, shall, at any time within the period of six months immediately following the commencement of this Act, be permitted to enter Kenya and to remain in Kenya for a period of ninety days, and shall be issued with a pass to that effect under this Act: Provided that this section shall not apply to a person who has not at any time been resident in Kenya since the 12th December 1963. 6 of 1972, s. 5, 22 of 1987, Sch., 13 of 1988, Sch., 5 of 2007, s. 6. SCHEDULE (s. 5) Classes of Entry Permits Class A: (1) A person who is offered specific employment by a specific employer, who is qualified to undertake that employment, and whose engagement in that employment will be of benefit to Kenya. (2) A person may be granted a “Class A” interim permit which shall be valid for six months. Class B: A person who is offered specific employment by the Government of Kenya or any other person or authority under the control of the Government and whose engagement in that employment will be of benefit to Kenya. Class C: A person who is offered specific employment under an approved technical aid scheme under the United Nations Organisation or some other approved Agency (not being an exempted person under section 4 (3) and whose engagement in that employment will be of benefit to Kenya.