If thats a button on the underside, its a Hella light.
Push the button and pull the upoer housing staight out, lead with the bottom.
Go gently and slow.
Look on bottom to see if Hella, then go on line for a oarts diagram and you might see how it works.
You shouldnt have to remove the nameboard for thed major brands I know of.
The owner of the boat next to me did the same thing a couple of years ago. When the LED failed, he had to replace the whole running light. Hope you have better luck.On my boat it takes zero. I replaced all the running lights with new LED fixtures.