If you have NOT filed your 2019 tax return, just click on My Info on the left side of the online program screen when accessing the 2019 tax return and delete the dependent.
If you have filed the 2019 tax return, you will have to amend the tax return to remove the dependent.
An amended tax return, Form 1040X, can only be printed, signed, dated and mailed by you to the IRS, it cannot be e-filed. The IRS will take up to 4 months to process the amended tax return. Wait until you have received the tax refund or the taxes owed have been paid and processed by the IRS before amending the tax return.