To remove a webhook for an event you'll need to reference the webhook_id, which can be found when you List Web Hooks. Once you've obtained the webhook_id, you'll user the DELETE method with the webhook endpoint.
DELETE /v1/environment/webhooks/:webhook_id
DELETE /v1/environment/webhooks/5491 HTTP/1.1
Host: api.shipengine.com
API-Key: __YOUR_API_KEY_HERE__You will receive a HTTP 204, (No Content) response if deleting the web hook was successful.
WARNING:
Be sure to confirm which webhook you are deleting. Once you've removed a webhook, the only way to restore it is to create a new one.