SDCL § 3-13-90: In-plan Roth conversion--Irrevocable.

A participant may convert the participant's pre-tax contributions to designated Roth contributions within the plan. The amount of the in-plan Roth conversion is subject to ordinary income taxes in the year of the conversion. Withholding of federal income tax from the conversion amount is prohibited. Once an in-plan Roth conversion is processed, the conversion is irrevocable. The amount of an in-plan Roth conversion must continue to be taken into consideration for mandatory distributions. The plan must establish and maintain separate recordkeeping for any in-plan Roth conversion made within the plan and must record the year that the participant first made a conversion.