Recharacterization explanation

I'm prompted for an explanation for recharacterizing my roth contribution to traditional IRA. The form includes the amount I'm recharacterizing, but it shows blanks for the dates of the contribution. It does not allow me to fill those parts out. I made those changes with the information through my brokerage account. Will that account for those dates or am I supposed to enter those dates on the explanation window. If so, how? If not should I just proceed with filing?

posted