Depending upon the size of the accounts of the terminated participants, the plan document may permit the administrator to request the individuals to take a distribution or IRA rollover, and in the absence of an election, force out the amounts. The plan administrator (or employer's HR office) could also be proactive, reach out to the terminated employees, and inform them of their options with respect to their account balances, including taking cash distributions or rollovers to the current plan or an IRA.