Best practices for switching extension from PJSIP to SIP?

Have a Sangoma phone provisioned with EPM linked to a PJSIP extension.

What are the recommended steps for switching said extension from PJSIP to SIP?
What I tried:

  1. Drop PJSIP extension.
  2. Unsassign extension to linked user (would not let me proceed to step 3).
  3. Recreate extension as SIP.
  4. Go to EPM and try to map extension to phone… except extension is not available for mapping???
    If I try to map the phone via the extension’s interface (under “Other”) EPM will list the mapping but the phone never gets any config files. The phone boots and correctly queries the FreePBX box for a config file but whatever it gets is devoid of any settings…