According to Title V – U.S. Code 3581-3584 and Executive Order 11552, U.S. Government Federal Agencies can detail or transfer an employee to any organization that the Department of State has designated an international organization.
A detail or transfer may not exceed 5 years but may be extended 3 additional years upon the approval of the head of the agency and the Assistant Secretary of the Bureau of International Organization Affairs.
Employees who transferred are entitled to be reemployed (as provided in 5 CFR 352 Subpart C) in his or her former position or one of like status within 30 days of his or her application for reemployment subject to prior approval by the Federal Agency concerned.
Upon reemployment, an employee is entitled to the same rate of pay he or she would have been entitled to had he or she remained continuously in the Federal service. The employee is entitled to have his or her sick leave restored to its status at the time he or she left the Federal service.