# Does the Cloud Voice App support number rewriting?

Yes. The Cloud Voice App supports number rewriting. It does not change the number on your device. Instead, it sends your call through an outbound route on the phone system, and that route applies the rewriting rules before the call is dialed out.

Number rewriting is a rule that adjusts the digits of a call before it leaves the system (for example, adding or stripping a prefix) so the call reaches the carrier in the format the carrier expects.

## How it works

Number rewriting lives on the outbound route, so the feature only takes effect when your call is sent through a route configured for it. An outbound route is a rule on the PBX (Private Branch Exchange, the phone system that handles your organization's calls) that decides which trunk a call leaves on and can modify the dialed digits on the way out. This setup happens on the phone system, not in the app.

:::note
You cannot create or edit outbound routes from the Cloud Voice App. Route configuration, including the number rewriting rules, is done on the phone system by your administrator.
:::

1. Ask your system administrator to create an outbound route with the number rewriting rules you need, and to grant your extension permission to use that route.
2. In the Cloud Voice App, choose that outbound route when you place the call. The system then applies the route's rewriting rules before dialing out.

![Selecting an outbound route in the Cloud Voice App dialer before placing a call](/images/pbx/mobile-dial-through-pbx.png)

:::caution
The digits actually sent to the carrier depend on which outbound route you pick, because each route can rewrite the number differently. Confirm you have selected the intended route before placing the call.
:::

:::note
If you do not see the route you expect, confirm with your administrator that the outbound route exists and that your extension has been granted permission to use it.
:::