So if inlet probe icing is suspected in ice crystal icing, the checklist says to select EPR engines to Alternate mode to restore proper thrust setting.
I accept that as a selectable precaution (pilot action) if indeed they suspect they will enter icing.
However, when you are caught off unawares, it's the engine certificated job to accommodate the threat on its own (by virtue of sense and response via the EEC etc.).
I realize that the EEC may be caught by newly encountered problems from time to time and that temporary work- arounds may find their way into FCOMs but in the end the problem needs to be addressed either under limitations of where you fly or by the engine itself before it becomes a glider.