You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to change in my plans to visit Dallas, I would like to change my existing reservation. Will you help me with this?

ASSISTANT: Sure, can I have your name to check the reservation status?

USER: My name is Rebecca Jackson.

ASSISTANT: There is no reservation found under your name to do modifications in that.

USER: Ok, not an issue. May be something went wrong while booking.

ASSISTANT: Yes, may be.

USER: Thank you for providing information.

ASSISTANT: Thank you for choosing us.