Iowa Code § 558.31: Proof of execution and delivery in lieu of acknowledgment.

Proof of the due and voluntary execution and delivery of a deed or other instrument may be made before any officer authorized to take acknowledgments, by one competent person other than the vendee or other person to whom the instrument is executed, in the following cases:

1. If the grantor dies before making the acknowledgment.

2. If the grantor’s attendance cannot be procured.

3. If, having appeared, the grantor refuses to acknowledge the execution of the instrument.