What should I do if I took someone as a sutrah during prayer and then they left their place: should I move forward or stay in my place?

The sutrah for the worshipper is recommended according to the majority of jurists, and obligatory according to some. It is Sunnah for the Imam and the one praying alone, but not for the follower. It is sufficient to protect the worshipper's gaze and enhance his humility. The matter that diverts the command from being obligatory is the Hadith of Al-Fadl ibn Abbas (may Allah be pleased with them both) that the Prophet (peace be upon him) prayed in a desert without a sutrah in front of him. It is permissible to use a person who is praying or sitting as a sutrah, and if they leave, and there is a nearby sutrah such as a wall or a pillar, it is permissible to move forward or backward to it if it is close; otherwise, one should complete the prayer and repel passersby.