Troubleshooting Frame Relay
Reconfiguring a subinterface

Once a specific type of subinterface has been created, it cannot be changed without a reload. For example, subinterface serial0.2 multipoint cannot be changed to subinterface serial0.2 point-to-point. To make a change, either reload the router or create another subinterface. This is the way the Frame Relay code works in Cisco IOSĀ® software.