Under Settings > General Settings, on the Fix CDR Dialing Pattern tab, you can specify the dialing prefixes that you want to remove from the view in the CDR report, on the Realtime page, and in webhooks.

To add a new prefix to the list, just type it in the box above the table and click the Add New Prefix button.

The prefix will be removed automatically from the pages mentioned above.

Click Delete under Actions to remove the prefix from this list and make it visible again.