You can quickly stop new requests being submitted by patients to control online demand by using the request limiter buttons on the unassigned inbox.
You can read why you may want to do this in this article.
What are patients told to do when PATCHS is switched off?
You can read about this in this help article for patients.
What happens if I already use the request limiter function?
If you already have request limits set in PATCHS, if you use the off switches you will over-ride any schedule you have set. Patients won't be able to submit requests regardless of what you have put in the table. They also won't be able to see when PATCHS is next open for requests if you have chosen to display that information. You can read more about the request limiter here.