You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what kind of assistance are you looking for?

USER: I am a traveller and to explore the new places in Denver, unfortunately due to sudden demise of my grand mother My planning to visit Denver has been postponed.So I would like to alter my existing reservation. Would you please help me in changing my existing reservation?

ASSISTANT: I can definitely do that on your behalf.

USER: Thank you for accepting my request.

ASSISTANT: Can you please share your name on which it was reserved earlier?

USER: You can check the reservation with the name of Lisa Gonzalez.

ASSISTANT: Ok, please allow me few minutes to check the current status and get back to you with an update.

USER: Sure, I would be waiting for your response.

ASSISTANT: Thanks for being patient, I have gone through the list but could not find any reservation active by the name Lisa Gonzalez in our data base.

USER: Ok, no issues at all.Thank you for your information.

ASSISTANT: Thank you consulting us.