Final answer:
It is true that a patient can revoke an authorization after signing it, this action is a reflection of the principle of autonomy which is essential in healthcare and clinical settings.
Step-by-step explanation:
The statement is true: After signing an authorization, a patient can decide to revoke it. The principle of autonomy affirms that patients have the right to make decisions about their own healthcare. This includes the capacity to consent to and also withdraw consent from medical treatments or participation in research studies. Revoking consent is a form of exercising one's autonomy, and it is a patient's right to do so at any point.
For example, in clinical settings, this principle is critical, and the informed consent process is a clear application of this right. Informed consent is not just a one-time event but an ongoing process, which means that a patient or research participant can reconsider and withdraw consent after having initially agreed.