I think the answer will be found in the condo declaration (or whatever your state calls the document creating the conditions and restrictions for condos).  In some states the owner who has use of the LCE will need to submit an amendment to the declaration to be approved by a vote of the condo board. 

It would make sense for the condo restrictions to insist on at least one garage unit remaining intact with the residential unit.

A question I would ask is whether the parking unit is always regarded as a LCE.  In Illinois, the units are sometimes taxed as a single parcel, with the unit owner having exclusive use of the parking space (LCE).  In other cases, the residential and parking units are taxed as separate parcels (maybe because of a difference in how the condo was set up).