Pronouncing Takbir on standing to make up for a missing part
If an Imam (leader of congregational Prayer) forgets part of the Salah, he does not have to pronounce Takbir to stand up and make up for it if he remembers or is alerted. However, if he pronounces Takbir when standing up to continue Salah, this does not affect the validity of Salah, as it is done to notify the Ma'mumin (persons led in Prayer) that he is going to continue Salah so that they follow him. Takbir is a form of permissible Dhikr (Remembrance of Allah) during Salah, thus it does not invalidate it.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.