F1 22 RESERVE DRIVER CUSTOM LEAGUE

Hello

I have a custom league going on, i am the owner, and next sunday its race time... One of my drivers is not gonna be able to make it.. is there any option to put the reserve driver in his place? I have 2 other drivers that ive got them as reserve drivers.. please answer ASAP as i need to fix all this really soon. I have the reserve option turned on but i cant find the way to add them.