If you said the closing salam before completing the prayer and then remembered, what do you do?

Question : Do you understand now? If this happened to you, and you said the salam before finishing, and then you remembered, what do you do? Do you return to the prayer and start over from the beginning, or do you build upon what you have already done?

Answer : You build upon what you have already done, say the salam, and prostrate twice after the salam, and fast, as the Prophet (peace and blessings be upon him) did. But if the time for breaking the fast was long, such that you did not remember until 'Asr, and you had asked about the Zuhr prayer, do you build upon it or repeat it from the beginning? You repeat it from the beginning, by the decree of Islam.