Before booking confirmation: you or the booking manager are entitled to change the set-up dates before accepting the requests, but never after.
After booking confirmation (after tenant’s payment): you or the booking manager are not entitled to change the set-up dates anymore and, thus, it will be contractually biding.
In exceptional circumstances, cancellations are possible only if the parties agree, according to the cancelation policy of the lease agreement.
Early check-outs are possible once the tenants advise the host, however, it does not change the set-up dates on the lease agreement.