Reported statements are one form of reported speech.

direct statementreported statement
He said, "I am sick."He said that he was sick.

We usually introduce reported statements with "reporting verbs" such as "say " or "tell":

  • He said (that)...
  • He told  me (that)...
When we report a statement, we can say "He said that ..." or simply "He said...". Both are possible. "He said that..." is more formal.

When we use our own words to report speech, there are one or two things that we sometimes change:

  • pronouns  may need to change to reflect a different perspective
  • tense  sometimes has to go back one tense (eg, present becomes past) - this is called backshift
  pronoun changetense change 
direct statementHe said,"Iamsick."
reported statementHe said (that)hewassick.

There are sometimes other things too that we may need to change, such as time or place . Look at these examples:

  pronoun changetense change time change
direct statementJane said,"Iwassickyesterday."
reported statementJane said (that)shehad beensickthe day before.
   tense change place change
direct statementShe said,"Itishot inhere."
reported statementShe said (that)itwashot inthere.

We also sometimes need to think about the third person singular "s":

  pronounperson change 
direct statementMary said,"Iworkin London."
reported statementMary said (that)sheworksin London.

Notice that in the above example, we do not change the tense. Usually, with the present simple, if something is still true now - she still works in London - we don't need to change it.

Typical reporting verbs for statements: say, tell, mention, inform

He said that...
He said...
He told me that...
He told me...
He mentioned that...
He informed me that...

sources : Original Link