bermuda02

just wondering, If you have been sponsored by a hospital for a greencard and approved etc and then by some miracle retrogression gets to your priority date.....who owns the greencard if you have already worked at the hospital then had to leave because the visa you were on expired before the greencard became current. Is it yours and then you can work wherever or does it belong to the hospital and if they don't have work or whatever can deny you your greencard even though you already worked for them intially? I would appreciate any responses.