What is the best way for a guest to extend their stay

[Clare0]

@Sue42 Easy, you or your guest can alter the reservation to add one more day.  Here's how:

https://www.airbnb.com/help/article/50/change-a-reservation-as-a-host

https://www.airbnb.com/help/article/913/change-a-reservation-as-a-guest

Hope this helps!