Clear the area under the sink
Place a bucket or towel under the drain
Open the sink cabinet
Locate the pivot rod connected to the stopper assembly
Loosen the retaining nut on the pivot rod
Pull the pivot rod out of the drain pipe
Lift the stopper straight up and out of the drain
Remove any stopper linkage or clip if attached
Clean the stopper and drain opening if needed
Reassemble the parts in reverse order if reinstalling