Well, you technically summoned Saber.

Were it possible to summon one's other self from a world to work them, would it not be equally possible for them to summon oneself to work one ?

Claverhouse said:

Were it possible to summon one's other self from a world to work them, would it not be equally possible for them to summon oneself to work one ?

Yep, that's why it's a summon-or-be-summoned multiverse.

Claverhouse said:

Were it possible to summon one's other self from a world to work them, would it not be equally possible for them to summon oneself to work one ?

It happened in Fate/Strange Fake.