Kairos ability for rerolls

[Tizianolol]

Guys I have seen a similar discussion on this forum time ago . Exemple : if i reroll a charge with archaon in tzeentch army. Can i use kairos ability to modify a dice from the reroll? 

Second question : can i use destiny dice to reroll a charge? Thx a lot!!

[jamie.white]

Destiny dice aren’t used to reroll , you use two to make the charge before you roll

[Tizianolol]

Ok thx ! What about kairos, can I modify a dice after a charge reroll?:)

[Landohammer]

5 hours ago, Tizianolol said:

Ok thx ! What about kairos, can I modify a dice after a charge reroll?:)

Yes. There is nothing preventing you from modifying a reroll. 

[Rellsipels]

On 3/12/2021 at 3:10 PM, Tizianolol said:

Ok thx ! What about kairos, can I modify a dice after a charge reroll?:)

I wold say no.

Q: Some abilities allow you to either pick, change or replace a 
dice roll with the roll of your choice. Does this happen before or 
after any re-rolls or modifiers?
A: Unless noted otherwise in the ability, it happens 
before any re-rolls or modifiers are applied.

From pg. 3 of the designers' commentary. Don't know if it's specified somewhere else but accordong to this I would say that you can't change the dice of a re-roll unfortunately.