[Home](./index.md) > [sip.js](./sip.js.md) > [Registerer](./sip.js.registerer.md) > [unregister](./sip.js.registerer.unregister.md) ## Registerer.unregister() method Sends the REGISTER request with expires equal to zero. Rejects with `RequestPendingError` if a REGISTER request is already in progress. Signature: ```typescript unregister(options?: RegistererUnregisterOptions): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | options | RegistererUnregisterOptions | | Returns: `Promise`