You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Susan Thomas.

ASSISTANT: How may I help you out?

USER: I want to change an existing reservation due o sudden change in my trip. Can you help me?

ASSISTANT: Sure, I will help you in changing the ticket.

USER: Thank you.

ASSISTANT: Sorry, there are no reservations found.

USER: No issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the information.