(1) Where the validity of a declaration of intention is to be affected by reason of absence of intention, fraud, duress, or by reason of knowledge or negligent ignorance of certain circumstances, the existence or non-existence of such reasons shall be determined on the basis of the agent.
(2) Where a principal entrusts a specific juristic act to an agent and the agent performs such act in accordance with the instructions of the principal, the principal may not assert the agent's lack of knowledge with respect to circumstances of which the principal was aware or failed to know due to his or her own negligence.