seceded

/S IH0 S IY1 D IH0 D/
verb
  1. 1

    To split from or to withdraw from membership of a political union, an alliance or an organisation.

  2. 2

    To split or to withdraw one or more constituent entities from membership of a political union, an alliance or an organisation.

Source: https://en.wiktionary.org/wiki/secede, https://en.wiktionary.org/wiki/seceded