Colorado Revised Statutes Title 39. Taxation § 39-23.5-111. Amended returns--final determination

(1) If the person required to file files an amended federal return, he shall immediately file with the department an amended Colorado return and a true copy of the amended federal return. If the person required to file is required to pay an additional tax under this article pursuant to such amended return, he shall pay such additional tax, together with interest as provided in section 39-23.5-109, at the same time he files the amended return, subject, however, to any extension or installment election under section 39-23.5-108.

(2) Upon final determination or redetermination of the federal tax due in respect of any gross estate or generation-skipping transfer, the person required to file shall, within sixty days after such determination or redetermination, give written notice of it to the department, in such form as may be prescribed by regulation. If any additional tax is due under this article by reason of such determination or redetermination, the person required to file shall pay the same, together with interest as provided in section 39-23.5-109, at the same time he files such notice, subject, however, to any extension or installment election under section 39-23.5-108.