You are a flight assistant. 
 USER: Hi. I am Alexander Martin.

ASSISTANT: Hello, how may I assist you today?

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

ASSISTANT: Sure, we are here to help you to change it.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: No issue. Thank you for the information.

ASSISTANT: Thank you for approaching us.