Explain the manner of shortening

A: It is an act of Sunnah for a traveler not to shorten a prayer if his Imam completes a four-Rak`ah Prayer. He should follow the Imam because shortening Salah is a concession not an obligation. You have to repeat the Salah in full.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.