1) Reported speech is used to report what someone said in the past by changing verbs and some words to the past tense while retaining the same meaning. 2) Common changes in reported speech include changing present tenses to past tenses, pronouns like "I" and "you" to "he/she/they" and "me/you" and changing place and time words like "now" to "then". 3) There are specific structures used for reporting requests, orders, offers and promises that involve using a reporting verb like "asked", "ordered" followed by an object and an infinitive verb. Pronouns also need to be changed.