If this verb is in the present tense, it's easy. We just put 'she says' and then the sentence:

• Direct speech: I like ice cream.
• Reported speech: She says (that) she likes ice cream.

We don't need to change the tense, though probably we do need to change the 'person' from 'I' to 'she', for example. We also may need to change words like 'my' and 'your'.

But, if the reporting verb is in the past tense, then usually we change the tenses in the reported speech:

• Direct speech: I like ice cream.
• Reported speech: She said (that) she liked ice cream.

• Tense	Direct Speech	Reported Speech
  present simple	I like ice cream	She said (that) she liked ice cream.
  present continuous	I am living in London	She said (that) she was living in London.
  past simple	I bought a car	She said (that) she had bought a car OR She said (that) she bought a car.
  past continuous	I was walking along the street	She said (that) she had been walking along the street.
  present perfect	I haven't seen Julie	She said (that) she hadn't seen Julie.
  past perfect*	I had taken English lessons before	She said (that) she had taken English lessons before.
  will	I'll see you later	She said (that) she would see me later.
  would*	I would help, but..”	She said (that) she would help but...
  can	I can speak perfect English	She said (that) she could speak perfect English.
  could*	I could swim when I was four	She said (that) she could swim when she was four.
  shall	I shall come later	She said (that) she would come later.
  should*	I should call my mother	She said (that) she should call her mother
  might*	I might be late	She said (that) she might be late
  must	I must study at the weekend	She said (that) she must study at the weekend OR She said she had to study at the weekend

  * doesn't change.
  Occasionally, we don't need to change the present tense into the past if the information in direct speech is still true (but this is only for things which are general facts, and even then usually we like to change the tense)
• In reported statements, we can use either 'say' or 'tell'. The meaning is the same, but the grammar is different. For example:
  Direct speech:
  • John: "I'll be late".
  Reported speech:
  • John said (that) he would be late.
  OR
  • John told me (that) he was going to be late.
  With 'tell' we NEED the object (e.g. 'me', 'you', 'her').
  With 'say' we CAN'T use the object (e.g. 'me', 'them', 'us').
  So we CAN'T say:
  • “John said me that he would be late.”
  • “John told that he would be late.”