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# refer

> Transfer a SIP call to an external endpoint via SIP REFER.

[transfer]: /docs/server-sdks/reference/typescript/relay/call/transfer

[calling-call-refer]: /docs/server-sdks/reference/typescript/relay/call#events

[call-events]: /docs/server-sdks/reference/typescript/relay/call#events

Transfer a SIP call to an external SIP endpoint using the SIP REFER method.
Unlike [`transfer()`][transfer]
which transfers control within Relay, `refer()` performs a SIP-level transfer
to an external endpoint.

> **Info**
>
> This method emits [`calling.call.refer`][calling-call-refer] events. See [Call Events][call-events] for payload details.

## **Parameters**

**`device`** `Record<string, unknown>` — required

The target SIP device for the REFER.

---

**`device.type`** `string` — required

Device type. Typically `"sip"`.

---

**`device.params`** `Record<string, unknown>` — required

SIP parameters including `uri` (the SIP URI to refer to).

---

**`statusUrl`** `string | undefined`

URL to receive REFER status webhooks.

---

## **Returns**

`Promise<Record<string, unknown>>` -- Server response confirming the refer operation.

## **Example**

```typescript {13}
import { RelayClient } from '@signalwire/sdk';

const client = new RelayClient({
  project: process.env.SIGNALWIRE_PROJECT_ID!,
  token: process.env.SIGNALWIRE_API_TOKEN!,
  contexts: ['default']
});

client.onCall(async (call) => {
  await call.answer();
  await call.play([{ type: 'tts', text: 'Transferring to another line.' }]);

  const result = await call.refer({
    type: 'sip',
    params: { uri: 'sip:support@example.com' },
  });
  console.log(`SIP REFER result: ${JSON.stringify(result)}`);
});

await client.run();
```

> Transfer a SIP call to an external endpoint via SIP REFER.