In accordance with IRS regulations, there are specific time periods in which employees may elect or change their pre-tax benefits. Those are as follows:
Post tax deductions, which do not require a designated enrollment period, may be changed at any time.
Employees who separate from service, dependents who reach age 26 and "age out" of the plan, and ex-spouses who were previously covered, are eligible for COBRA benefits, once they terminate from the plan.