You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I need to change my reservation due to urgent meeting, can you help me?

ASSISTANT: Yes, can you tell me your name?

USER: I am Melissa Lee.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's ok. Thank you for your help.

ASSISTANT: Thank you for reaching us.