* It allows to change the backend elected as default backend, the default backend is the device used for all operation (for example tsys) when a schedule is not running.
* It allows to change the backend elected as default backend, the default backend is the device used for all operation (for example tsys) when a schedule is not running.
* @param bckName name of the instance of the backend that has to be placed as default backend. It couls be also an alias assigned to this backend
* @param bckName name of the instance of the backend that has to be placed as default backend. It could be also an alias assigned to this backend