Iowa Code § 490.742: Demand.

A shareholder shall not commence a derivative proceeding until both of the following have occurred:

1. A written demand has been made upon the corporation to take suitable action.

2. Ninety days have expired from the date delivery of the demand was made, unless the shareholder has earlier been notified that the demand has been rejected by the corporation or unless irreparable injury to the corporation would result by waiting for the expiration of the ninety-day period.