Ariz. Rev. Stat. § 43-401
B. An employer may voluntarily elect to not withhold tax during December by notifying:
F. Before July 1 of each year, each employer who chooses to not withhold tax pursuant to subsection B of this section shall notify each employee that:
G. At an employee's written request, the employer may agree to reduce the amount withheld under this section by the amount of credit that the employee represents to the employer that the employee will qualify for and be entitled to under sections 43-1088, 43-1089, 43-1089.01 and 43-1089.03. The employee's request must include the name and address of the qualifying charitable organization, qualified school tuition organization or public school. Within thirty days after agreeing to the employee's request, the employer shall reduce the withholding amount by the amount of the credit, but not below zero, prorated for the number of pay periods remaining in the employee's taxable year after the employee makes the request. If an employer agrees to reduce the withholding amount pursuant to this subsection, the following apply: