Transaction-based services are increasingly being applied in solving many universal interoperability problems. Exception and failure are the typical phenomena of the execution of long-running transactions. To accommodate these new program features, we extend the Guarded Command Language by addition of compensation and coordination combinators, and enrich the standard design model with new health- iness conditions. This paper shows that such an extension is conservative one because it preserves the algebraic laws for designs, which can be used to reduce all programs to a normal form algebraically. We also explore a Galois link between the standard design model with our new model, and show that the embedding from the former to the latter is actually a homomorphism.