1. A computer-implemented method, comprising: receiving first input information describing changes between a first process template and a second process template; receiving second input information characterizing a grouping of the changes; applying the changes to the first process template in a complete grouping, as defined by the second input information, to identify a set of combinations of the first process template and the second process template; and migrating an instance of the first process template to a respective combination of the set of combinations, wherein the respective combination containing complete groups of changes defined by the second input information that affect only a future of the instance at a time of migration.