You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donald Lopez here.

ASSISTANT: Good evening, welcome to airlines booking agency. How can I guide you Lopez?

USER: I would like to change my reservation because I have another important work on that day, can you please help me out with changing of my reservation?

ASSISTANT: Sure, wait for a minute to check it, I will revert you after finding any ticket booking.

USER: Sure, take your time.

ASSISTANT: Thank you for your patience. I am unable to find your booking which you have booked earlier to modify it.

USER: Oh, so sad to hear. Anyways, thank you for the information.

ASSISTANT: Thank you for choosing our agency, have a nice day Lopez.

USER: Welcome.

ASSISTANT: It's our pleasure.