Turn off the power to the smoke detector at the circuit breaker if it is hardwired
Twist the detector counterclockwise to remove it from the mounting bracket
Disconnect the wiring harness by pressing the release tab and pulling the connector apart
Remove the battery if it is battery-powered or has a backup battery
If the unit is interconnected, disconnect each linked detector as needed
Replace the detector or reconnect power when finished
Test the detector after reinstalling or restoring power