When certificate takes effect

(A) First certificate furnished A withholding allowance certificate furnished the employer in cases in which no previous such certificate is in effect shall take effect as of the beginning of the first payroll period ending, or the first payment of wages made without regard to a payroll period, on or after the date on which such certificate is so furnished.

(B) Furnished to take place of existing certificate (i) In general Except as provided in clauses (ii) and (iii), a withholding allowance certificate furnished to the employer in cases in which a previous such certificate is in effect shall take effect as of the beginning of the 1st payroll period ending (or the 1st payment of wages made without regard to a payroll period) on or after the 30th day after the day on which such certificate is so furnished. (ii) Employer may elect earlier effective date At the election of the employer, a certificate described in clause (i) may be made effective beginning with any payment of wages made on or after the day on which the certificate is so furnished and before the 30th day referred to in clause (i). (iii) Change of status which affects next year Any certificate furnished pursuant to paragraph (2)(C) shall not take effect, and may not be made effective, with respect to any payment of wages made in the calendar year in which the certificate is furnished.