There are two ways of relating what a person has said: direct and indirect.
    In direct speech we repeat the original speaker’s exact words:
    e.g. He said, “I want to go home”.
    Remarks are placed between inverted commas, and a comma or colon is placed immediately before the remark.
    In indirect speech we give the exact meaning of a speech, without necessarily using the speaker’s exact words:
    e.g. He said (that) he wanted to go home.
    There is no comma after say in indirect speech; that can usually be omitted after say and tell + object.
    When we turn direct speech into indirect, some changes are necessary.
    After present, future and present perfect reporting verbs, tenses are usually the same as in the original:
    e.g. I’ll tell her your idea is great.
           Tom says he doesn’t want to play any more.
           The government has announced that taxes will be raised.
    After past reporting verbs, the verbs of the original speech are usually “backshifted” – made more past. In this case the rule of sequence of tenses is applied. The changes are shown in the following table:
    Simple Present
    He said, “I like my new house”.
    Simple Past
    He said (that) he liked his new house.
    Present Continuous
    He said, “I am waiting for her”.
    Past Continuous
    He said (that) he was waiting for her.
    Present Perfect
    He said, “I have found her key”.
    Past Perfect
    He said (that) he had found her key.
    Present Perfect Continuous
    He said, “The baby has been sleeping  for 2 hours”.
    Past Perfect Continuous
    He said (that) the baby had been sleeping for 2 hours.
    Simple Past
    He said, “I took her to the cinema with me”.
    Past Perfect
    He said (that) he had taken her to the cinema with him.
    He said, “I’ll ask Tom to help me”.
    He said (that) he would ask Tom to help him.
    Future Continuous
    He said, “I’ll be using the car myself on the 10th”.
    Conditional Continuous
    He said (that) he would be using the car himself on the 10th.
    Past tenses are often left unchanged, if this can be done without causing confusion about the relative times of the action.
    e.g. He said, “Ann arrived on Monday”.
            He said Ann arrived (or had arrived) on Monday.
            He said, “When I saw them they were playing tennis”.
            He said that when he saw them they were playing tennis.
    Would, should, ought to, might, used to, could and must usually remain unchanged.
    e.g. He said, “Ann might ring any minute”.
            He said that Ann might ring any minute.
            He said, “I should be back by 10”.
            He said that he should be back by 10.
    Pronouns and possessive adjectives usually change from first or second to third person except when the speaker is reporting his own words:
    e.g. He said, “I like my new shoes”.
            He said that he liked his new shoes.
    But I said, “I like my new shoes”.
            I said that I liked my new shoes. (the speaker is reporting his own words)
    In indirect speech adverbs and adverbial phrases of time and place as well as demonstrative pronouns change as follows:
    that day
    the day before
    the day before yesterday
    two days before
    the next day / the following day 
    the day after tomorrow
    in two days’ time
    next week / year etc.
    the following week / year etc.
    last week / year etc.
    the previous week / day etc.
    a year ago
    a year before / the previous year
    Indirect statements are normally introduced by say, or tell + object (person addressed).
    e.g. He said he had just heard the news.
            He told me that he had just heard the news.
    Say can introduce a direct statement or follow it:
    e.g. Tom said, “I’ll do it tomorrow”.
            “I’ll do it tomorrow”, Tom said.
    Inversion of say and noun subject is possible when say follows the statement:
    e.g. “I’ll do it tomorrow”, said Tom.
    When we turn direct questions into indirect, the following changes are necessary.
    Tenses, pronouns and possessive adjectives, and adverbs of time and place change as in statements. The interrogative form of the verb changes to the affirmative form. The question mark (?) is omitted in indirect questions. If the introductory verb is say, it must be changed to a verb of inquiry, e.g. ask, inquire, wonder etc.
    e.g. He said, “Where is the bus stop?”
            He asked where the bus stop was.
            He said, “Why is she crying?”
            He wondered why she was crying.
    If the direct question begins with a question word (when, where, how, who, why etc.) the question word is repeated in the indirect question.
    If there is no question word, if or whether must be used:
    e.g. He said, “Did you see the accident?”
            He asked if / whether I had seen the accident.
            The policeman said, “Do you know Paul Smith?”
            The policeman inquired if / whether I knew Paul Smith.
    Indirect command, requests, advice are usually expressed by a verb of command, request, advice + object + infinitive. The following verbs can be used instead of say: tell, order, ask, recommend, advise.
    e.g.  He said, “Close the door”.
            He told / ordered me to close the door. (We must add a noun or pronoun.)
            He said, “Turn on the radio, please”.
            He asked me to turn on the radio. (Please is omitted.)
    Negative commands, requests etc. are normally reported by not + infinitive:
    e.g. He said, “Don’t interrupt me, Tom”.
            He told Tom not to interrupt him.
            He said, “Don’t go away, please”.
            He asked me not to go away.
    Exclamations usually become statements in indirect speech. The exclamation mark disappears. Exclamations beginning with What (a)…. or How ….. can be reported by exclaim or say that:
    e.g. He said, “What an awful idea!”                  or      “How awful!”
            He exclaimed that it was an awful idea.      or      He said that it was awful. 
    Note also:
            He said, “Thank you!”                             He thanked me.
            He said, “Good luck!”                             He wished me luck.
            He said, “Happy Christmas!                    He wished me a happy Christmas.
            He said, “Congratulations!”                     He congratulated me.
            He said, “Liar!”                                        He called me a liar.
            He said, “Damn!”                                     He swore.
    Yes and No are expressed in indirect speech by subject + appropriate auxiliary verb:
    e.g. He said, “Can you drive?” and I said, “No”.
            He asked if I could drive and I said I couldn’t.
    Direct speech may consist of statement + question, question + command, command + statement. Normally each requires its own introductory verb, but sometimes we can use as instead of a second introductory verb:
    e.g. He said, “I am going shopping. Can I get you anything?”
           He said he was going shopping and asked if he could get me anything.
          He said, “You’d better wear a coat. It’s very cold out”.
          He advised me to wear a coat as it was very cold out.