You are a flight assistant. 
 USER: Hello. Joseph Thomas here.

ASSISTANT: Hello. How may I help you today?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, I am happy to help you with that. Can I know your travelling dates?

USER: Previously my travel dates were 06/22 to 06/24.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there no is reservation found on your name in our database.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for your reaching us.