You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I guide you?

USER: My name is Sandra Phillips.

ASSISTANT: Hello Sandra.

USER: Due to an accident to my friend, I would like to change my existing reservation. Could you please help me?

ASSISTANT: Sorry, that's sad to hear. Wait a moment to check your details.

USER: Sure.

ASSISTANT: Sorry Sandra, there is no reservation found under your name.

USER: That's ok.

ASSISTANT: Do you have any other preferable dates?

USER: No. Thank you for the information.

ASSISTANT: Thank you for reaching us.