depends on what type of led that it is, on how easy it is. if it's a 3mm or 5mm led bulb, you can usually just get another led and clip the wires and solder them or electrical tape if you have to.
if they are smd led's, those are harder to desloder and replace but can be done if you are good at soldering.
the other thing to consider is how much voltage is the led circuit currently putting out. sometimes led's of different colors need different forward voltages.