A mobile station (129) will have the capability to detect an impending cell change and Routing Area Update (RAU) and will send a “Request Deny” message to the network via the serving cell prior to handing over. The PTT server (131) will use the Request Deny message as an indication that an inter-SGSN RAU may be occurring. The PTT server (131) will wait for the mobile station to reappear, after handover, on a new cell. If the mobile does not reappear, an inter-SGSN RAU may be assumed and the PTT server (131) will release the floor and deny the floor to all mobile stations. This action forces all mobile stations back into idle mode and prevents them from seizing the floor. The PTT server (131) will then wait for the mobile station (129) performing the RAU to reappear on a new cell before opening the floor to all mobile stations.