There are many ways to influence preffered route within EIGRP one of which is changing the delay value on the interface. Although many details about changing metrics you can get from http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c2d96.shtml article, all I want here is to show how it may go in practice.
Let’s take a very simple topology - two L3 devices are connected with redundand links like in the picture below:
Assume we do not need load balancing here and change the delay so that only one route remains in the routing table. As the result the traffic flow may change in the way we don’t want it to be. Like in the picture below.
To level things one can increase the delay on the opposite side of the connection.