Identify the stopper type
Lift the stopper to the open position
Look for a set screw, knob, or cap
Unscrew the top cap if present
Loosen any visible set screw with an Allen wrench
Pull the stopper straight up and out
Twist counterclockwise if it is threaded
Remove the linkage from the overflow plate if needed
Use pliers gently if the stopper is stuck
Clean the drain opening after removal