### Answer --- You can update SIP trunk settings for an already imported phone number using the Update Phone Number API. [(1) ]() The following fields can be updated for custom telephony numbers: -

termination_uri

– The termination URI used for outbound calls -

auth_username

– The username for SIP trunk authentication -

auth_password

– The password for SIP trunk authentication -

transport

– Outbound transport protocol (

TLS

,

TCP

, or

UDP

) Example:

javascript
import Retell from 'retell-sdk';
const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const phoneNumberResponse = await client.phoneNumber.update('+14157774444', {
  inbound_agent_id: 'oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD',
  nickname: 'Frontdesk Number',
  outbound_agent_id: 'oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD',
}) ;
console.log(phoneNumberResponse.inbound_agent_id) ;

Note: The FAQ in the Custom Telephony Overview states: "I need to change the configuration of the imported number, how can I do that? Right now you'd need to delete and re-import the number." [(2) ]() However, the Update Phone Number API does expose

termination_uri

,

auth_username

,

auth_password

, and

transport

fields for updating. [(1) ]()

​ To learn more, see the sources I considered: [[1] Update Phone Number](https://docs.retellai.com/api-references/update-phone-number) [[2] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer --- I don't have information in the available sources about editing SIP trunk phone number settings through the Retell AI dashboard UI. Based on the previous response in this thread, the Custom Telephony Overview FAQ states that to change the configuration of an imported number, you would need to delete and re-import the number. If you need to avoid using the API, the UI workflow would likely be: 1. Delete the existing phone number from the dashboard 2. Re-import it with the updated SIP trunk settings Check out these potentially useful sources: - [Update Phone Number]() - [Custom Telephony Overview]() - [Platform Changelogs | Retell AI]() Would you like a general answer based on my knowledge instead?

message has been deleted

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.