You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

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

ASSISTANT: Sure, I can help you. May I know your name?

USER: My name is Andrew Nelson.

ASSISTANT: We didnt found any reservation by this name.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for choosing us.