Iowa Code Title XIII. Commerce [Chs. 505-554D] § 538.7. Nonacceptance of tender

When a tender of money or property is not accepted by the party to whom it is made, the party making it may, if that party sees fit, retain it in possession; but if afterwards the party to whom the tender was made concludes to accept it and gives notice thereof to the other party, and the subject of the tender is not delivered to the accepting party within a reasonable time, the tender shall be of no effect.