An Amended Tax Return is filed to correct any errors or to update information provided on the originally filed return. There is a timeline under which you need to submit the amended return to the IRS. Often an amended state return must be filed as well.
Should the amended tax return create a balance due, a payment should be made promptly. Penalties and interest may be assessed. If the amended return results in a refund, the tax authorities will process it accordingly.
You can file an additional Amended US tax return if further corrections are required. Generally, it is preferable to wait until the first Amended tax return is processed by the IRS and then file the second Amended return.
In the case of balance due, you can opt not to make the payment reflected on first Amended tax return. Instead, you can file the second Amended tax return and pay the taxing authority the balance due on the second Amended tax return filed.