The LEDs in question are surface mount components. The easiest (and proper) way to work on surface mount components is with a hot-air rework station. Typically, one would use a combination of solder paste and hot air.
First, heat components until solder is molten, then pick them from the board. Second, clean the residual solder from the pads with a desoldering wick or vacuum. Third, apply solder paste to pads. Fourth, place the new components on the pasted pads. Lastly, heat the components until the paste turns molten and wait for the board to cool until reinstallation.
Just don't heat things for too long. :biggrin: