To replace a click plank without disassembling the entire floor, cut into the damaged plank so that you can get your hand or a tool into it to pop it out. The seam may be a good starting point for this, but to avoid the risk of damaging the plank next to it, you can gouge a spot in the middle of the plank you want to replace.
At this point, take a replacement plank and cut the click mechanisms off the "groove" or "female" edges (since you won't be able to click it in). You will also need to cut off the neighboring male edges. Glue both the new plank and the neighboring planks with cut-off male edges in place using a quality construction adhesive. Be careful not to apply too much adhesive, or the adhesive may come up between the seams and create a mess.
First, to help make a cut or hole:
Second, to help pry/pop out damaged plank:
Third, to trim off click mechanism:
Fourth, to glue down: