You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Sandra Miller.

ASSISTANT: How can I help you?

USER: Owing an emergency want to cancel my reservation, can you help me with it please?

ASSISTANT: Sure, let me check your reservation details in our database.

USER: Ok, take your time.

ASSISTANT: Sorry, I did not find any reservation by your name in our database.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for choosing us.