D.C. Mun. Regs. tit. 6, r. 6-B232
A reassignment occurs when an employee is permanently moved from one position to another at the same or equivalent grade within an agency or to another agency under the same personnel authority.
A personnel authority may reassign an employee to another position when the reassignment is to a position in the same service (Career or Educational) at an equivalent grade with no additional promotional potential, and the employee is qualified for the new position.
Whenever a reassignment alters the substantive rights or benefits of an employee, the employee must agree to the reassignment in writing. Substantive rights and benefits include, but are not limited to, employee movements from a unionized position to a non-unionized position and a change in the employee's enhanced suitability requirements.
D.C. Mun. Regs. tit. 6, r. 6-B232