You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please share me your name.

USER: I am Jack Clark.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no active reservation on your name.

USER: No issue. Thank you.

ASSISTANT: Thank you.