Guest changes booking dates, what date is used for cancellation policy, original or new one?

[Dave52]

If a guest changes their dates (and host accepts), will original check in date or new check-in date will be used for the cancellation policy. 

Example:  guest books 1/29-1/31,

On 1/28 guest requests to change to 2/15-2/17, host accepts the change. 

Listing has a Moderate cancellation policy (cancel up to 5 days before check in).

Guest cancels on 2/1. 

->Airbnb support tells me in this case the guest won't get a full refund.  Can someone confirm this?  

[Esther824]

In such a case, I found it best to ask CS to change the dates as non-refundable. I do offer a non-refundable booking option. Albeit, the change would not have a discount  I also communicate this to the guest prior to accepting a change. No problems so far.