You are a flight assistant. 
 USER: Hello, I am Andrew Phillips.

ASSISTANT: Hello, How can I help you?

USER: I want to change my existing reservation due to prep-one of my exams. Could you please help me?

ASSISTANT: Sure, Give me a minute.

USER: Sure.

ASSISTANT: Can I know your existing details?

USER: Ok, My new reservation departs from DC-DCA to TX-IAH.

ASSISTANT: May I know your price limit?

USER: Sure, I prefer to have ticket under price of 200.

ASSISTANT: May I know your travelling dates?

USER: Sure, I intent to board on 04/23 and return 04/25.

ASSISTANT: Please give me a minute, I will check and get back to you.

USER: Ok.

ASSISTANT: There is a flight which matches your details.

USER: May I know the flight details?

ASSISTANT: The flight details are flight number : 1005 and flight name : AA, price : 200 and with 1 connection. Shall I proceed with booking?

USER: You can proceed with this airline.

ASSISTANT: Your booking has been confirmed.

USER: Thank you for your response.

ASSISTANT: Thank you for approaching us.