You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Jason Smith.

ASSISTANT: How can I render you Smith?

USER: I just want to change my existing reservation, due to sudden demise of my grand mother.

ASSISTANT: Sure, I am here to help you, please wait for a while.

USER: Sure.

ASSISTANT: Sorry Jason Smith, no reservation done on your name previously.

USER: Ok fine, thanks for your assistance.

ASSISTANT: Thank you for reaching us.