You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Virginia Clark.

ASSISTANT: How can I assist you today?

USER: As my plans to visit Dallas was postponed, can you please help me in changing my existing reservation?

ASSISTANT: Sure, please be on hold while I'll check your reservation status.

USER: Sure, take your own time.

ASSISTANT: Clark, there is no reservation found under your name to do changes in that.

USER: Ok, not an issue. Thank you for the information provided.

ASSISTANT: Thank you for choosing us.