You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I need to change my reservation due to my planned event got shifted to another dates so please help me with that.

ASSISTANT: Sure, please provide me your name to check the reservation details on your name?

USER: Sure, myself Robert Thomas.

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Thomas, no reservation found on your name in our data base. Thank you for reaching us.