Update audio file on the phone

Update the content of an existing audio file by recording yourself over the phone.
For a given audio file sid, this method will return a phone number and a code to
enter as DTMF to record yourself.

Once you have confirmed the changes over the phone, the content will be processed
asynchronously. The status property of the updated audio file will transition
through the following stages:

• pending-conversion
• processing
• Finally, it will be either ready or error

You can use webhooks to receive updates on the status.