How do you repair a blown head gasket on a 97 Chrysler Concorde?
Take it off, replace the gasket
A blown gasket can be repaired by replacing the gasket...if you are talking about the head gasket, then you have to remove the cylinder head from the engine block and replace the gasket that is inbetween them. Cracked heads generally have to be replaced because they are made of aluminum which cannot be repaired permanently once it is cracked.
A thermostat gasket is a gasket for a thermostat, a head gasket is a head gasket. The top part of the engine needs to be disassembled to repair the head gasket. You can find information on your specific car in your local library. You may even be able to access this online if the library has the databases available.