[Home](./index.md) > [sip.js](./sip.js.md) > [Session](./sip.js.session.md) > [prack](./sip.js.session.prack.md) ## Session.prack() method Send PRACK request. Acknowledge a reliable provisional response. https://tools.ietf.org/html/rfc3262\#section-4 Signature: ```typescript prack(delegate?: OutgoingRequestDelegate, options?: RequestOptions): OutgoingPrackRequest; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | delegate | OutgoingRequestDelegate | Request delegate. | | options | RequestOptions | Options bucket. | Returns: `OutgoingPrackRequest`