Climb a ladder for close access to the panel.
Score the seams carefully with a utility knife to sever the joints. Cut a square hole out of the middle of the panel to create an edge for inserting a pry bar.
Remove the panel by inserting a pry bar in the center hole you've created. Trying to pry off the panel from the seams can damage adjacent tiles.
Remove any nails or staples from the furring strips with the pry bar.
Scrape off old adhesive from the furring strips with a putty knife.
Apply a bead of panel adhesive to the furring strips. Panel adhesive comes in a caulk tube and is extruded from a caulk gun.
Cut the tongue off one edge of a new ceiling panel so it will fit into the hole.
Insert the remaining tongue into the groove of an adjacent ceiling panel and press the panel onto the adhesive.
Climb a ladder for close access to the panel.
Push up on the panel with both hands and pop it out of the tracks.
Turn the panel at an angle, then bring it down and out of the grid.
Hold a new panel at an angle and slide it up through the empty space.
Position the panel flatly and lower it onto the tracks.