To remove a unit from the stack, disconnect the cables from the stacking ports. This can be done whether the units are powered on or powered off. When you remove a unit that is powered on, it is still in stacking-enabled mode. To remove the stacking files, enter the stack unconfigure me or stack unconfigure clean command.
The "stack unconfigure me" command returns a unit to the state it had before joining a stack and recovers its startup configuration. The stack unconfigure clean command removes the unit's startup configuration. When you issue either command, the unit operates as a standalone unit once it reboots.