Turn off the faucet and clear the sink area
Open the cabinet under the sink
Locate the pop-up lift rod or stopper linkage behind the drain pipe
Disconnect the horizontal pivot rod from the clevis or retaining clip
Pull the pivot rod out of the drain body
Lift the sink plug straight up and out of the drain
If the plug is stuck, twist it gently while lifting
Remove any debris or buildup from the drain opening
Reinsert the plug if needed, or replace it with a new one
Reconnect the pivot rod and linkage if you want the stopper working again