A new monarch assumes the royal prerogative as soon as his or her predecessor dies or abdicates. The Constitution stipulates that the new monarch must be sworn in and invested as soon as possible.
The Constitution also stipulates that the investiture must take place in the capital city, Amsterdam, at a public joint session of the two Houses of the States General (Parliament) – the Senate and House of Representatives. The monarch swears or affirms allegiance to the Charter for the Kingdom of the Netherlands and the Constitution. The wording of the oath or affirmation is laid down by statute.
The oath or affirmation of allegiance to the Charter for the Kingdom of the Netherlands and the Constitution
‘I solemnly swear (affirm) to the peoples of the Kingdom that I shall constantly preserve and uphold the Charter for the Kingdom of the Netherlands and the Constitution. I swear (affirm) that I shall defend and preserve the independence and the territory of the Kingdom to the best of my ability, that I shall protect the freedoms and rights of all Dutch nationals and all persons living in the Netherlands, and that I shall employ all means placed at My disposal by the law to support and promote the welfare of all, as is incumbent upon a good and faithful King.
So help me God! (This I affirm and promise)’