Question

He said, "I will come here again tomorrow.​

Answer 1

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He said that he would go there again the next day.

Explanation ↴

In the Direct & Indirect Speech, we usually change the tense of the Direct Speech when we change it to the Reported speech, but in the case of Future Simple tense we do not change the tense of the direct speech after converting it to the reported speech.

The Helping verb of Future Simple tense will convert to 'would' in the Indirect (reported) Speech and the word 'come' will convert to 'go' in the Indirect speech.

Answer 2

He said that he would go there again the next day.

The Helping verb of Future Simple tense will convert to 'would' in the Indirect (reported) Speech and the word 'come' will convert to 'go' in the Indirect speech.

☇Hope it helps☇