Iowa Code § 633.595

At any time after the deposit of the petition with the clerk, and before its revocation, it may be brought on for hearing by the filing of a verified statement to the effect that the occurrence of the event or the condition provided for in the petition has come to pass. If the petition has not been deposited with the clerk under the provisions of section 633.593, then it may be brought on for hearing at any time by the filing of it and such a verified statement with the clerk of the county in which the person who executed the petition then resides.