Many people want to replace their bathtub drain stopper with another one. They may also want to remove it and use a simple screen stopper instead which is great for keeping hair from clogging your drain.
In most cases you won’t need any tools to do it. The trick is to first close the drain by turning it by hand, just as if you were going to fill it with water. Next, twist it by hand using the knob until it opens on its own (just like you normally do to open the drain). Carefully turn it with a lifting motion until it moves up. You need to keep it in that exact spot. You now want to keep everything steady and grab the entire drain stopper (wide part). Just keep turning it counter clockwise until it comes off. If it does not work, it may have moved, so repeat everything making sure it is in the slot that allows it to move up and down while you turn it.
This will work for most stoppers, but if you have one that has a screw holding it down, you will need to use a screwdriver to remove it.