You are a flight assistant. 
 USER: Hi. Gregory Roberts here.

ASSISTANT: Hello. How can I assist you?

USER: Last week I booked a flight ticket with your agency for my holiday trip to New York, but due to my health concerns I am unable to make it to my trip. So can you cancel my flight ticket reservation?

ASSISTANT: Can you please tell me your travelling dates?

USER: I do not have travel dates. Cancel the flight ticket.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: sorry, no reservation found on your name to cancel.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.