The purpose of this research study is to determine how effective and how safe it is to give an Epstein-Barr Virus (EBV) immunotherapy product to participants with nasopharyngeal carcinoma (NPC) associated with EBV that has come back or spread to other parts of the participants body. The EBV immunotherapy product will be made with white blood cells from the participants blood and takes about 16 weeks to create. This EBV immunotherapy product may stop cancer cells from growing and cause the tumors to disappear.