from: https://www.thebalance.com/what-to-do-if-you-contributed-too-much-to-your-roth-ira-3192888
Withdraw the Excess Contribution
A withdrawal is the removal of assets from a retirement account so the amount withdrawn doesn't count toward a person's contributions for that particular tax year. According to the IRS, you can withdraw contributions on or before the due date for filing your tax return.
You must also withdraw any earnings on the excess contributions. Earnings are considered earned and received in the tax year during which the excess contribution was made.
You can withdraw contributions from a Roth IRA up until the Oct. 15 extended deadline if you've requested an extension of time to file your tax return. Withdrawals aren't treated as distributions; they're like an "undo" function. It's as though the contribution was never made in the first place.
