switch (someone or something) through (to someone or something)
To connect or transfer someone's telephone call (to someone or something else). He's in a meeting right now, but I can switch you through to the board room if it's an emergency. Please hold—I'll switch your call through in a moment. They've been trying to switch us through to him, but he's not picking up.
switch someone or something through
to connect someone or something with something else. I will switch you through the priority network. The operator switched the call through.