You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Due to an emergency, I want to change my reservation. Can  you help me?

ASSISTANT: Sure, I will help you with that but I need your name to check the reservation details.

USER: John Gonzalez here.

ASSISTANT: Sorry, I could not find any reservation with your name in our database.

USER: No problem, Thanks for the information.

ASSISTANT: Thanks for choosing us.