Multiply classes for same endpoint

Hi everyone,

if I have an interface marked as ServiceContract, and some method marked as OperationContract.

After that I have 2 classes implementing that interface and two different behaviours for a method in the interface.

How we can specify which implmentation we need to use when we hit that endpoint?

[ServiceContract]
public interface IServiceContract
{
    [OperationContract]
    void SomeMethod();
}
 
public class ImplementationClassA : IServiceContract
{
    public void SomeMethod()
    {
        // Implementation for Class A
    }
}
 
public class ImplementationClassB : IServiceContract
{
    public void SomeMethod()
    {
        // Implementation for Class B
    }
}