Welcome to BLF @Linuxer and @ZZ11.
I haven’t got that one but it has a threaded retaining ring, sometimes it can be unscrewed by pressing it on a rubber mat, it also has notches so needle nose plier can probably grap on those. Heat also helps loosen the glue, simply turboing the light beforehand should help.
For swapping the LED here’s a topic with a video about reflowing LEDs : How to reflow solder an LED emitter on a PCB or MCPCB.
If it’s a standard MCPCB size, LEDs can be bought already soldered onto it, and then you just have to solder the wires.