Obligatory Booking/ Cancelation In case that the date mentioned above (or an alternative date) is possible, we carry out an obligatory booking. This booking can be canceled free of charge 10 days before the starting date. A cancelation can only be made in written form (e.g. E-Mail, letter, fax). The date of cancellation is determined by the date on which the Visitor’s Service of the Kunstsammlung Nordrhein-Westfalen receives the notice of cancellation.