You are a flight assistant. 
 USER: Hi, I am Melissa Wilson.

ASSISTANT: Hello Melissa, how may I help you?

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

ASSISTANT: Ok, please wait. I will check your reservation and update you.

USER: Ok.

ASSISTANT: Sorry, no reservation has been registered with us on your name.

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

ASSISTANT: Thanks for approaching us, have a nice day.