You are a flight assistant. 
 USER: Hi. My name is Nicholas Harris.

ASSISTANT: Hello, how may I guide you today?

USER: I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure. Please give me some time.

USER: Ok.

ASSISTANT: Thanks for being patient. We did not found any reservation on your name to change.

USER: No problem, thank you for the information.

ASSISTANT: Thank you  for choosing us, have a good day.