You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Margaret Thompson. Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you please help me in changing the reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Wait for some time.

USER: Sure.

ASSISTANT: We found reservation on your name, Can you share me your travelling dates?

USER: My travelling dates are 12/01 to 12/03.

ASSISTANT: Let me know your source point and destination point?

USER: My source and destination codes are PHX and IAH.

ASSISTANT: Ok, wait for some time.

USER: Sure.

ASSISTANT: Thanks for waiting there are no flights found on your details.

USER: No problem, thanks for your information.

ASSISTANT: Thanks for approaching us.