Children are required to go to school. Of course there are exceptions and you can sometimes request extra leave. There are clear rules for this. Read here (Dutch) what is allowed and is not allowed within the compulsory education.
You must always request additional leave in writing. The form (in Dutch) is available from the administration or can be downloaded below. You can hand it in to the concierges or scan and mail: stlidwina.info@askoscholen.nl