755 ILCS 43/50
A declaration may be revoked in whole or in part by written statement at any time by the principal if the principal is not incapable, regardless of whether the written revocation is in an electronic or hard copy format. A written statement of revocation is effective when signed by the principal and a physician and the principal delivers the revocation to the attending physician. An electronic declaration may be revoked electronically using a generic, technology-neutral system in which each user is assigned a unique identifier that is securely maintained and in a manner that meets the regulatory requirements for a digital or electronic signature. Compliance with the standards defined in the Uniform Electronic Transactions Act or the implementing rules of the Hospital Licensing Act for medical record entry authentication for author validation of the documentation, content accuracy, and completeness meets this standard. The attending physician shall note the revocation as part of the principal's medical record.
755 ILCS 43/50