Если слова автора стоят в Present Simple (Indefinite), Present Perfect или Future Simple, то в косвенной речи время не меняется.
Если слова автора стоят в Past Simple, Past Continuous или Past Perfect, то в косвенной речи время меняется в зависимости от того, какое время было в прямой.
The secretary has said that the press conference is taking place now in the main hall.
My brother has said that Aunt Sally will come on Monday.
The students have said that they had two tests last week.
Her daughter said that she wasn't listening to music then.
My friend said that he had visited all those places.
Tom said that he was a first year student then.
She said that she hadn't been speaking to him since the day before.
Susan said that she had been in the library two days before.
The boy said that he hadn't been watching TV at home at 8 o’clock.
The teacher said that they had been writing since early morning.
He said that he would visit me the following Friday.
She said that she would be leaving her home at 10 o’clock that night.