Send to a specialist, say

REFER

Think of what a doctor might do when they want a second opinion from another professional.

The clue plays on the double meaning of "refer." In everyday language, you might "refer" someone to a specialist, like a doctor sending a patient to a cardiologist. But it also works as a self-contained definition—the word itself literally means to direct someone to an expert or authority. The "say" hints that this is just one example of how the word could be used.