Indirect speech changes exactly three things: the pronouns, the tense, and the words of time and place.

The quotation marks come off and a 'that' goes in, but those are bookkeeping. The three shifts are the whole subject, and each has its own card in this deck.

He said, "I am busy today." → He said that he was busy that day.

pronoun, tense and time word all shift

He said that I am busy today.

nothing shifted at all

Where it bites

Doing two of the three. A candidate who shifts the tense and forgets the time word loses the mark as completely as one who shifts nothing.