To clarify, do you mean excess contribution the the Roth IRA because of your modified adjusted gross income (MAGI) is too high and you want to recharacterize it to a traditional IRA? Then yes, it would be good to wait until you recharacterized the amount before filing so you can enter all the correct information.
If you have a excess contribution to the Roth IRA then you can recharacterize it as a traditional IRA contribution, make it nondeductible and then later convert it to a Roth IRA.
If you choose to recharacterize the contribution then you will have to tell your bank this before the due date.
You will enter the recharacterization when you enter the contribution to the Roth IRA
If this does not answer your question then please provide more details.