Effective change management requires structured planning, testing, review, approval, deployment, and rollback capabilities. According to CompTIA Security+ SY0-701, one of the most critical components of change management is having a backout plan, which allows the organization to safely revert changes if the update or patch causes issues, operational disruption, or security instability. A proper backout plan reduces downtime, maintains system availability, and protects against unexpected failures.

Approving a change after deployment (A) violates standard change management protocols. Approval must occur before live implementation. Using a spreadsheet (C) is not considered an effective or secure change management mechanism. Automatic bypassing of change controls (D) is dangerous, even for security patches, because changes must be tested to avoid service outages or unintended vulnerabilities.

Therefore, the best description of effective change management is B: Having a backout plan when a patch fails.