CXone DFO API: Disconnecting a single participant from a conference

Trying to drop a specific leg from a conference call via the DFO API. I’m trying to disconnect a participant using the API with the correct bearer token. The request returns a 204 No Content, but the participant stays connected in the UI. I’ve verified the participant ID matches the one returned in the initial conversation payload. Am I missing a required header or is this endpoint behaving differently for DFO sessions?