Design patterns that can replace if statements

Our application is getting complex, it has mainly 3 flow and have to process based on this one of the 3 type. Many of these functionalities overlap each other.

So currently code is fully of if-else statements, it is all messed up and not organised. How to make a pattern so that 3 flows are clearly separated from each other but making use of power of re-usability.

Please provide some thoughts, this is a MVC application, where we need to produce and consume web servicees using jaxb technology.