In this particular case, deleting the tutorial is the only right thing to do. Of course the performance can stay up.
If in the future you come up with anything independently, it'd be best to ask around if people (magicians) have seen it before or if it might be original. If it seems original, you can release a tutorial of it. But if then anyone is able to prove someone else came up with the same thing before, you will have to add credits (to the trailer/performance/product page) which usually is all that needs to be done then. However, if before releasing a tutorial it's been proven that someone else came up with it before, deleting the tutorial (or simply.. not releasing it at all) is the only correct way of dealing with it.
Hope that helps.