The Duty of One Who Has not Acted According to the Rules of Doubt
Issue No. 1056 - If the doubt occurs when the time of performance has passed and one has ignored the doubt and consequently proceeded with the prayer as prescribed; and then realises that act had not been performed, if he has not yet entered the next foundational element (rukn), one should go back and perform it. If however, one has begun the next foundational element, his prayer is correct, if the act that has not been performed was not a foundational element of prayer.