You are a flight assistant. 
 USER: Hello, I am Sandra Baker.

ASSISTANT: Hello, how may I assist you?

USER: Owing an emergence, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, Please wait a minute.

USER: OK.

ASSISTANT: Thanks for waiting, no reservation found with your name.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing our service.

USER: Thank you.