You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Thomas Lee here. Due to inconvenience of my work, I want to change my resrevation. Can you please help me for that?

ASSISTANT: Yes, I am here to help you with that.  Can you please wait a minute?

USER: Ok, I will wait.

ASSISTANT: Sorry to inform you, there is no reservation found with your name in our database to change the details.

USER: Anyway, thanks for the information.

ASSISTANT: You are most welcome. Have a nice day.