According to this:
Suicide Hotline: What Happens When You Call? - HealthyPlace

Will the Police Get Called If I'm Suicidal and Call a Suicide Hotline?

This is a tricky question and the answer is neither "yes" nor "no." In the vast majority of cases, no police (or other authority) involvement is required and in the cases where emergency help is needed, suicide hotline staff will make every attempt to gain permission to send them. The goal of a suicide hotline is to help you with your personal crisis and no one-size-fits-all solution is possible.

That being said, if you are actively suicidal and threatening to imminently hurt yourself, it is possible that emergency personnel may be called without your permission. While no one likes that scenario, it truly is the best, lifesaving thing an operator can do in a small number of cases.