A conferencing system includes a plurality of ports for network connection to endpoint devices of participants to a conference session. A mixer receives input audio streams from the endpoint devices and then outputs a mixed audio stream back to the endpoint devices. A processor runs a program that automatically downgrades one or more of the participants to the conference session from a full-duplex communication mode to a half-duplex communication mode in response to an event affecting allocation of conferencing resources, the conferencing resources including the ports. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.