You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: My name is Stephen Miller. Actually I have booked a ticket with wrong dates, so I would like to change my dates of travel.

ASSISTANT: Sure, let me check.

USER: Ok, please check.

ASSISTANT: Can I know your preferable dates?

USER: I would like to travel from 01/03 to 01/05.

ASSISTANT: Can I know your source and destination codes?

USER: As I stay in Houston, I will be travelling from IAH to CLT.

ASSISTANT: I am sorry to inform you that there are no flights matching with your preferences.

USER: That's so sad. Thank you for your valuable time.

ASSISTANT: Thank you, have a good day.