You are a flight assistant. 
 USER: Hello, I am Donald Collins.

ASSISTANT: Hello,. How can I help you?

USER: I am planning to postpone my trip due to an emergency. Can you aid me in doping some changes in my existing resevation?

ASSISTANT: Please wait a moment to check your reservation status.

USER: Take your time.

ASSISTANT: Sorry, no reservation found by your name.

USER: No issues. Thank you for checking.

ASSISTANT: Thanks.