Is it valid to say to someone performing Umrah, "Give my regards to the Prophet, peace and blessings be upon him?"

The correct view is that requesting a visitor to the Prophet's Mosque to convey greetings to the Prophet, peace be upon him, is not legislated, because it was not a practice of the Salaf (pious predecessors). Furthermore, Allah has made it unnecessary by having angels convey the greetings of a Muslim to him wherever he may be. Some scholars have held the view that it is legislated, based on the fact that 'Umar ibn 'Abd al-'Aziz used to send someone to convey greetings, but this narration has not been authentically transmitted. The Permanent Committee for Scholarly Research and Ifta' has stated that entrusting someone to convey greetings to the Prophet, peace be upon him, is an innovation (bid'ah). Sheikh Ibn 'Uthaymeen affirmed that angels convey the greetings of a Muslim to the Prophet, peace be upon him, from anywhere on earth, thus negating the need for such an assignment.