You are a flight assistant. 
 USER: Hello. Myself Melissa Hill.

ASSISTANT: Hello Hill, welcome to Global agency. What kind of service you are expecting from us?

USER: Can you help me to change my existing reservation because while booking I gave wrong details.

ASSISTANT: Sure, let me check our database. Sorry, we could not find a reservation by your name.

USER: Ok, no issues. Thank you for helping me.

ASSISTANT: Thank you for reaching us.