This is a feature Zynga throws on every now and then. Usually happens about once every month or so, but it is active now for a limited time.
You can reallocate 50 skills for 50 RP or 10 skills for 10 RP. This can be accessed through the Marketplace "Stat Items" tab. If you are a rebuilder, then you can use this to your advantage. The most logical way to reallocate is to pull from Health as it is the easiest to recoup.
Be sure to read the instructions. In this screen you are picking from which skill you will be pulling.
You will then have to go to your profile page to allocate them as you'd like.
Here's the logic with reallocation. From building, the most skills you can gain for each is as follows:
Attack: 6 (Stun Knuckles)
Defense: 6 (Hack Blade)
Health: 20 (Warthog, Wildebeest)
Energy: 6 (Solar Flare)
Stamina: 6 (Rebel 2, Robber's Utility Belt)
Additional Total Skills: 7 (Dirty Trick - 5 Health + 2 Stamina, Electric Prod - 5 Health + 2 Energy).
So, if you wanted to add to anything (except health), the logic is that you pay 50 RP to pull from health, then use rebuilds (x3) to replace the health. For 86 RP, you can gain 60 skills, which is way better than the 12 RP:4 Skills you can buy outright or any of the 12 RP:6 attack/defense/energy/stamina rebuilds.
Long story short - if you are a player who uses RP to rebuild for additional attack/defense/energy/stamina and have at least 86 RP, then this is the best way to spend your RP. If you like to rebuild for health (20 health for 12 RP), this is not for you. And finally, if you spend your RP on limited time loot, boosts, or energy/stamina refills, this is not for you. Good luck everyone!! (and thanks Claire for the pictures).