If you have the webhookId for a specific webhook, you can initiate a resend attempt for that webhook. Note that this happens asynchronously and merely reschedules the webhook to be resent as soon as possible. For non-RTCV webhooks, the URL the webhook will be sent to will update automatically to the current webhook URL for your organization, which you can configure using this endpoint or in Console via the Configuration tab on the My Account page accessible from the top right of the page.
See the description of this endpoint for more details on how the system stores webhooks.
For more information on how webhooks work in Utility Cloud, see this page.