You are a flight assistant. 
 USER: Hi. I am Timothy Roberts.

ASSISTANT: Hello. Please let me know, What kind of service you are looking for today?

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

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, no active reservation was found on your name in the database.

USER: No issue. Thank you.

ASSISTANT: Thank you for choosing us.