1. Tense Changes
1.1. Present Simple into Past Simple
1.1.1. She always wears a coat. - He said (that) she always wore a coat.
1.2. Present Continuous into Past Continuous
1.2.1. I'm looking for my keys. - She said (that) she was looking for her keys.
1.3. Present Perfect into Past Perfect
1.3.1. She has written three letters for her friend. - He said (that) she had written three letters for her friend.
1.4. Present Perfect Continuous into Past Perfect Continuous
1.4.1. I've been waiting for you for half an hour. - He told me (that) he had been waiting for me for half an hour.
1.5. Past Simple into Past Perfect
1.5.1. My friend gave me a bar of chocolate. - He said (that) his friend had given him a bar of chocolate.
1.6. Past Continuous into Past Perfect Continuous
1.6.1. I was sleeping at 5 o'clock. - He said (that) he had been sleeping at 5 o'clock.
1.7. Past Perfect (The tense remains unchanged)
1.7.1. I had been interviewing candidates. - She said (that) he had been interviewing candidates.
1.8. will into would
1.8.1. I will finish my report in two days. - He said (that) he would finish his report in two days.
2. Other Verb Form Changes
2.1. can into could
2.1.1. I can speak English. - She said (that) she could speak English.
2.2. could (The verb remains unchanged)
2.2.1. I could help her. - She said (that) she could help her.
2.3. have to into had to
2.3.1. I have to submit this assignment by 3 p.m tomorrow. - She said (that) she had to submit this assignment by 3 p.m tomorrow.
2.4. must into must/had to
2.4.1. I must go to the bank and get some money. - She said (that) she had to go to the bank and get some money.
2.5. may into might
2.5.1. I may invite them to dinner. - She said (that) she might invite them to the dinner.
2.6. might (The verb remains unchanged)
2.6.1. I might go to the zoo. - He said (that) he might go to the zoo.
2.7. should (The verb remains unchanged)
2.7.1. We should take the exam. - They said (that) they should take the exam.
3. Changes in Time and Place
3.1. now into then
3.1.1. The children are playing outside now. - He said that the children were playing outside then.
3.2. today into that day
3.2.1. I've got a piano lesson today. - She said that she had got a piano lesson that day.
3.3. here into there
3.3.1. Put the box here. - He told us to put the box there.
3.4. this into that
3.4.1. I shall be very busy this week. - She said she would be very busy that week.
3.5. tomorrow into the following day/the next day/the day after
3.5.1. I will leave for New York tomorrow. - She said (that) she would leave for New York the next day.
3.6. next week into the following week/the next week/the week after
3.6.1. I have an appointment next week. - She said that she had an appointment the following week.
3.7. yesterday into the previous day/the day before
3.7.1. Our English teacher quizzed us yesterday. - They said their English teacher had quizzed them the day before.
3.8. last week into the previous week/the week before
3.8.1. We had an awful earthquake last week. - They told us that he had had an awful earthquake the previous week.
3.9. ago into previously/before
3.9.1. The letter came a few days ago. - He said the letter had come a few days before.
3.10. tonight into that night
3.10.1. I'm going for a beer with Karl tonight. - He said that he was going for a beer with Karl that night.
4. Introductory Verbs
4.1. Tell, say, ask
4.1.1. Jack says: "Learn English!" - Jack tells to learn English.
4.2. Verb+that+clause: complain, deny, explain, exclaim, remark, promise, boast, inform somebody, claim, agree, suggest
4.2.1. "Yes, it's a big house". - He agreed that it was a big house.
4.3. verb+to+infinitive: agree, offer, refuse, demand, threaten, promise, claim
4.3.1. "Yes, I'll help you". - He agreed to help me.
4.4. verb+indirect object+to+infinitive: advise, allow, beg, command, encourage, forbid, invite, want, instruct, permit, urge, order, remind, warn
4.4.1. "You should see a doctor". - He advised me to see a doctor.
4.5. verb+ing form: admit (to), accuse somebody of, apologize for, boast about/of, complain to somebody of, deny, insist on, suggest
4.5.1. "Yes, I told her the secret". - He admitted telling her the secret.
5. No Change in Verb Tenses
5.1. The introductory verb is in the Present, Present Perfect or Future.
5.1.1. He says: "I will come". - He says (that) he will come.
5.2. If the reported sentence deals with a fact or general truth.
5.2.1. Copernicus: "The planets revolve around the sun". - Copernicus stated (that) the planets revolve around the sun.
5.3. The reported sentence contains a time clause.
5.3.1. She said: "His parents died while he was still at school". - She said (that) his parents died while he was still at school.
5.3.2. Had better, could, would, used to, should, might, ought to and mustn't remain unchanged.
5.3.2.1. He said: "Ann might ring today". - He said (that) Ann might ring that day.
5.4. The verb of the sentence is in the unreal past (the second or the third conditional).
5.4.1. He said: "If I won the lottery, I would travel around the world". - He said (that) he would travel around the world if he won the lottery.
5.5. The subjunctive stays unchanged in the subordinate clause.
5.5.1. The children said: "We wish we didn't have to take exams". - The children said they wished thay didn't have to take exams.
5.6. If the speaker reports something immediately or soon after it was said.
5.6.1. A: What did the teacher say? - He says we should write our lessons carefully.