Hi @tmiskiew,
Thanks for the post. If you would like to change the username of a participant, you may leverage the following interface in ZoomSDKMeetingActionController(https://zoom.github.io/zoom-sdk-macos/interface_zoom_s_d_k_meeting_action_controller.html#ad088d89806e6994d032dea94ea0b7093):
/**
* @brief Change user's screen name in the meeting.
* @param userID The ID of user whose screen name will be changed. Normal participants can change only their personal screen name while the host/co-host can change all participants' names.
* @param name The new screen name.
* @return If the function succeeds, it will return ZoomSDKError_success, otherwise not.
*/
- (ZoomSDKError)changeUserName:(unsigned int)userID newName:(NSString*)name;
Hope this helps. Thanks!