We often need to tell others what someone else said. There are two ways to do this. One is to say the same words and use quotation marks. That is "direct speech." The other method is to summarize, or tell about what someone said. This is called "reported speech."
Choose a reporting verb and tense
With current, repeated or recent events, the reporting verb is in the present tense: "He says he is hungry, so let's go to lunch."
A habitual or repeated statement is in the present tense: "Everyone says the water is safe to drink."
For reporting less immediate speech, choose the past tense.
The reporting verb is often said, but it can also be told, or other verbs like ordered, stated, or reported, depending on the situation. When reporting questions, you can use verbs like asked or requested.
Change the perspective, or point of view
That means I becomes he, she, or they.
Choose whether to include "that or "if."
You can say, "He says he is at home" or "He says that he is at home." That is a conjunction here, linking the two parts of the sentence; it is optional.
Another conjunction, if, is required when reporting on a question: "He asked me if I knew how to play tennis."
"Backshift" the tense
When the reporting verb (said, told etc) is in the past tense, the verb in the reported clause is in the past tense, too. The verb aspect, showing whether the action is completed, matches.
Reporting on questions
When we report questions, we have to pay attention to the auxiliary verb. These are words like do, be, and have. Yes or no questions begin with an auxiliary, but to report that question, drop the auxiliary and add if.
Information questions start with a question word; to report on these, simply change the pronoun and word order.
Reporting speech with modals
Finally, pay attention to whether the speech you are reporting uses a modal verb. Will, can, and shall change to would, could, and should when reported. Will is used to make statements about the future in English. When reporting this kind of statement, will becomes would.