In a distributed database system, at least one of the databases operates as a transaction manager and provides transparent commit coordination between an application program and other connected databases. The transaction manager incorporates a commit alteration procedure which enables selection of either a single phase commit protocol or a two phase commit protocol with respect to each database, during operation of the distributed system. The transaction manager establishes a commit protocol for each connected database; responds to a command from an application program by overriding a commit protocol previously established for a selected database and establishes another commit protocol for the selected database; performs a transaction and utilizes the another commit protocol in connection with the transaction; and upon completion of the transaction as evidenced by a successful commit action, enables establishment of another commit protocol.