You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Mark White here.

ASSISTANT: How can I help you today?

USER: Due to sudden change in my planned date of journey, I would like to change my reservation. Can you please help me out with changing of my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT:  Please wait a moment, I will check your reservation status.

USER: Sure, take your time.

ASSISTANT: There is no previous reservation available on your name Mark White.

USER: Oh! I think the ticket was not booked properly while I am booking. Thank you for the information.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Welcome.