Answer:
He said that he would do it the following week .
Explanation:
For statement we use said when reporting verb is said so - no change ,
connective - that ,
He is third person so for person change there is - - no change ...
There is - will + v 1
Changing it into indirect speech tense becomes - - would + v 1
For time adverbial , next week becomes the - - - - - - following week ...
