Enables emergency routing for your account and sets the number emergency calls are sent to, then regenerates and reloads the routing so it applies to the next call. The value is stored exactly as sent, with no format checking or cleanup, so send a number you have verified — a typo here silently misroutes emergency calls. The check for an existing setting and the write itself go to different places, so change this setting one call at a time rather than in parallel. Requires an API key with the Admin role.