You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I am Amy Robinson. I want to change my existing reservation due to postpone of my board meeting, so can you please help me in changing my reservation?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: We found a reservation with your given name, please share your new journey dates.

USER: My new journey dates are 4th Jan and 6th Jan.

ASSISTANT: Can you please share your source and destination airport codes?

USER: I am heading to IAH from OAK.

ASSISTANT: May I know your depart time and return time?

USER: I want to depart in the evening and return in the afternoon.

ASSISTANT: Do you have any other requirements?

USER: I need a single connecting flight.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for opting us.