The IRS has issued sample amendments to be used by plan sponsors who wish to add the Roth feature to their 401(k) plans. Access the amendments in Notice 2006-44. Excerpt from the Notice:
Plan sponsors who want to provide for designated Roth contributions in their § 401(k) plans must adopt a discretionary amendment as provided in Notice 2005-95, 2005-51 I.R.B. 1172. The deadline to adopt a discretionary amendment is the end of the plan year in which the amendment is effective, as set forth in section 5.05(3) of Rev. Proc. 2005-66. The timely adoption of the amendment must be evidenced by a written document that is signed and dated by the employer (including an adopting employer of a pre-approved plan).
The IRS states in the Notice that “the amendment will not result in the loss of reliance on a favorable opinion, advisory, or determination letter” nor will adoption of the sample plan amendment affect “the pre-approved status of a master and prototype or volume submitter plan.”