@Debra300
@L94 mentioned longer term stays, so I don't know if that's what the guests are trying to book. If so, and the stay is over 28 days, the long term policy will automatically apply and override the flexible policy. That means guests have to pay for the first month, but of course, they can still change their dates providing it's more than a month away (or ask the host after that).
Personally, I would be very worried taking a booking so far ahead and I would never opt for a flexible policy in the first place, but that's just me.