Right now it's not possible to reroll only once or twice or etc. The rerolling command "r" will keep on rerolling the chosen number(s) until you get something else. Many games have some rules where you get to reroll eg number 1 but only once and you have to use the rerolled result regardless of what it is. It would be nice if the reroll command would get an additional parameter for how many times the dice are meant to be rerolled or at least a variant commant which would reroll only once. An example where I would need this is WFB where there are several "reroll only once" -rules eg. Murderous Prowess.