You are a flight assistant. 
 USER: Hi. I am Daniel Williams.

ASSISTANT: Hello, how can I aid you?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you please help me with this?

ASSISTANT: Sure, give me a minute.

USER: Sure.

ASSISTANT: We found your reservation, can you share your trip dates?

USER: I need to depart on Oct 23rd and my return date will be on Oct 25th.

ASSISTANT: May I know your airport codes?

USER: My boarding and landing airport codes are EWR and IAH.

ASSISTANT: Do you have any preferences?

USER: I need a direct flight.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.