crosstitution
n.— «The derogatory term “crosstitution” has been used to describe the process—introduced by constitutional amendment—that allows politicians to move from one party to another without losing their seats.» —“ANC secures W Cape majority” by Reesha Chibba in Cape Town Mail & Guardian (Johannesburg, South Africa) Sept. 1, 2005. (source: Double-Tongued Dictionary)