If you want to change a reservation's dates or cancel it altogether, do so on the booking channel of origin. This will allow the change to update in SiteMinder and Guesty.
If you are unable to make the necessary changes in the booking channel, contact us to make them in Guesty. However, since this might not update in SiteMinder or the relevant booking channel, we recommend checking the booking channel of origin to make sure that the reservation is updated correctly.