Iowa Code § 44.9: Withdrawals.

Any candidate named under this chapter may withdraw the candidate’s nomination by a written request filed as follows:

1. In the office of the state commissioner, at least eighty-one days before the date of the election.

2. In the office of the appropriate commissioner, at least seventy-four days before the date of the election, except as otherwise provided in subsection 6.

3. In the office of the appropriate school board secretary, at least forty-two days before the day of a regularly scheduled school election.

4. In the office of the state commissioner, in case of a special election to fill vacancies in Congress or the general assembly, not more than:

a. Twenty days after the date on which the governor issues the call for a special election to be held on at least forty days’ notice.

b. Five days after the date on which the governor issues the call for a special election to be held on at least ten but less than forty days’ notice.

5. In the office of the appropriate commissioner or school board secretary in case of a special election to fill vacancies, at least twenty-five days before the day of election.

6. In the office of the appropriate commissioner, at least forty-two days before the regularly scheduled or special city election. However, for those cities that may be required to hold a primary election, at least sixty-three days before a regularly scheduled or special city election.