You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Carol Hall.

ASSISTANT: Ok.

USER: Owing to an emergency I want to change my existing reservation. Can you please help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: OK.

ASSISTANT: We found a reservation on your name. Can you please share your new travelling dates?

USER: My travelling dates are 06/23 to 06/25.

ASSISTANT: Ok, please help me with your airport codes.

USER: My airport codes are IAH - DCA.

ASSISTANT: Do you need any halt in between your journey?

USER: No, I need direct flight.

ASSISTANT: Wait a minute please.

USER: OK.

ASSISTANT: Thank you for waiting, sorry to inform you that we didn't find any flights with your details.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us, have a nice day.