Family staying at Airbnb for 2 nights - wants to extend stay at same rate. Is that possible

[Laurie308]

A family is wanting to book our AirBnb for 2 nights.  They might want to extend their stay one more night but are unsure if they will.  Are they able to extend their stay at the same rate?  

[Laurie308]

Is it better to have them book for 3 nights and cancel one if needed or book 2 nights and have them add the third, hoipefully at the same rate and with no service fee or cleaning charge?