Board Thread:Questions and Answers/@comment-31594898-20170326105723/@comment-93.16.135.125-20170326121539

Also, in a normal Fuyuki Grail War with the Servant system, no, a Servant can't change their class just by switching weapon. Gilgamesh doesn't become Saber, Lancer or Caster by grabbing hold of a different sword, spear or staff from his treasury. The Servant vessel is summoned once and that's it, that's the Servant system.