If you need to open a Panasonic filter, there are a few things that you will need to do. First, locate the release button on the top of the filter. Press this button down and hold it while you rotate the filter counterclockwise. This will cause the filter to release from the housing. Next, take out the old filter and dispose of it properly. To install the new filter, simply insert it into the housing and rotate it clockwise until it clicks into place.