Switch to a newsperson on the scene, say

GOLIVE

Think of what a broadcast team might shout when cutting to real-time coverage from the field.

This clue plays on the phrase "go live," which means to start broadcasting in real time—something a newsperson on the scene would do. The word "switch" hints at changing or activating something, reinforcing the idea of transitioning to a live feed. "GOLIVE" is written as one word here, which is common in crosswords for short phrases.