You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to some health issue, I am unable to travel now. Can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you for this. Let me check you reservation status in our records.

USER: Sure, I am Sandra Garcia.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry for inconvenience, no reservation is found with your criteria.

USER: Ok, Thank you.

ASSISTANT: Thank you very much for contacting our agency.