The main value of the agile methods, including Scrum, Kanban, XP practices, and others is that they help you focus on the result more than on the process of getting to the result.
While the process, and documentation, and meetings, and discussions, are all important, getting job done is the most important thing of all. Therefore, everything should be flexible to allow timely and effective delivery.
This requires regular and rigorous review of the practices, and consequent changes to make the delivery better. If you initially adopt Scrum, and then figure out that it is not working well for you, then you can change. The result may not be ‘Scrum’ per se, but your approach will be more agile than strict adherence to the process that may or may not deliver the results you seek.