You should first find employment in a TRS-eligible position. In addition, you must file with TRS either an Application for Restoration from Service Retirement (code GA1) or an Application for Voluntary Restoration from Disability Retirement (code DI20). The Application for Voluntary Restoration from Disability Retirement may be obtained by calling TRS at 1 (888) 8-NYC-TRS and speaking with one of our Member Services Representatives.