You enchant the leggings with empowered favors given at the end of the event. The amount of empowered favors you get depends on the total event favors you get.
To change tiers you need the icor and to enchant it you need selonas empowering favour. Changing tier is er breeches to skirt to belt, etc
I think everyone understood the question, the problem is that it is human nature that when a person does not have all the facts their minds fill in the missing information with crap. Some people think the crap makes sense and use that to respond while others push the crap away and continue to search for the truth. Sometimes the crap is based on prior experience but nonetheless it is still crap. This is what makes people think they know it all. This is also why people continue to answer your question even though they don't know the answer because people haven't been told how much it will cost to upgrade the equipment. If people were told you would have been able to research it yourself and there would have been no need for me to respond to this pointless thread.