  Controlling a complex network towards a desired state is of great importance
in many applications. A network can be controlled by inputting suitable
external signals into some selected nodes, which are called driver nodes.
Previous works found there exist two control modes in dense networks:
distributed and centralized modes. For networks with the distributed mode, most
of the nodes can be act as driver nodes; and those with the centralized mode,
most of the nodes never be the driver nodes. Here we present an efficient
algorithm to change the control type of nodes, from input nodes to redundant
nodes, which is done by reversing edges of the network. We conclude four
possible cases when reversing an edge and show the control mode can be changed
by reversing very few in-edges of driver nodes. We evaluate the performance of
our algorithm on both synthetic and real networks. The experimental results
show that the control mode of a network can be easily changed by reversing a
few elaborately selected edges, and the number of possible driver nodes is
dramatically decreased. Our methods provide the ability to design the desired
control modes of the network for different control scenarios, which may be used
in many application regions.
