Class which updates an object
There's no super-design-pattern that would be beneficial here, but you could definitely benefit from some basic OO concepts like encapsulation and single responsibility.

For starters, rather than making a bunch of utility methods, it's better design to allow each class a static method like:

// inside the ContestantObj class
public static ContestantObj fromID(string ID) {
   // code to retrieve ContestantObj 
}


This way, each class is responsible for creating itself, which it should be (outside of cases where a builder or abstract factory is required).

Your UpdateContestantObj constructor should take in a ContestantObj. It shouldn't care about how the ContestantObj is created. A "Contestant Updater" should be a machine that takes in Contestants and outputs Contestants that have been updated.

Also, the naming convention of ContestantObj should simply be Contestant. We know it's an object.