Reroll for event CE

No. Once you roll, that's it. The nature of gacha is that sometimes you don't anything.

Hello.
Lost 100K FP (all of it), 10 tickets, and no event CE at all.

Welcome to gacha hell.

I don't think you understand what rerolling actually means...

Rerolling refers to rerolling your account, as in creating a completely new one and rolling the gacha on that. You repeat until you end up with an account with something you want on it.

There is no way of redoing a bad roll on the same account.

For reroll, it have different meaning and have been mentioned above.
Also if you want to do the actuall reroll, make sure you have Generated your Transfer Code.
So you won't lose your precious acc and don't forget to keep and remember the Code.

Here, i thought you mean '' summoning trick/ritual '' for the targeted CE's.
Fine i'll gave you one. Do the FP 10x roll then if the result show 6-8 or more CE's, maybe SQ gacha can give you good CE's.