You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what help that I can aid you at this moment?

USER: I am David Smith, can you help me to change my reservation to next week?

ASSISTANT: Sure, I will help you. Please give me a moment to check it in our previous reservation list.

USER: Sure, please check.

ASSISTANT: Thank you for your patience, I have checked based on your request but it is showing that no flight ticket has booked under the name that you have mentioned us for checking purpose.

USER: Oh! ok, no issues. Thank you for your time.

ASSISTANT: It's my pleasure and have a great day. Thank you for reaching us.