Abstract: Workflow change is an important problem that often needs addressed in enterprise
business process, especially the cooperation in cross-enterprises. Contraposing that most
enterprises have widely applied PDM system, this paper proposes a VPDM(Virtual PDM) method
to solve workflow change among enterprises. Its realization mechanism is described, the
processing method and the procedure about the VPDM-based workflow change are both given
elaborate discussion, which is divided into two types, i.e. up to down change as well as down to
up change, and their dealing processes are presented, respectively. After that, ignorable activities
are described and a recursion judgment algorithm on them is introduced. A successful example
verifies feasibility of developed software on solving the problem of the change of workflows
during some sort of product’s research process.

Key words: VPDM, workflow, change, ignorable activity