How can I force cast a data to the generics specified in the method constraint?

I have the following data class and VM class:

public interface IData
{
    string Name
    {
        get;
    }
   }

public class DataPartial: IData
{

    public DataPartial()
    {


    }

    public string Name => "Data partial";
}

public class DataFull : IData
{
    public string Name => "Data full";

    public DataFull()
    {

    }
}

public interface IVM
{
    IData Data { get; }
}
public interface IVM_partial: IVM
{
  new  DataPartial Data { get; }
}


public class VM_Partial : IVM_partial
{
    public VM_Partial()
    {
        Data = new DataPartial();

    }
    public DataPartial Data { get; set; }

    IData IVM.Data => Data;
}
public interface IVM_Total:IVM_partial
{
   new DataFull Data { get; }
}



public class VM_Total : IVM_Total
{


    public VM_Total(IVM_partial dataA)
    {
        Data = new DataFull();
        DataA_interface = dataA;
    }

    public IVM_partial DataA_interface { get; }


    public DataFull Data { get; private set; }

    DataPartial IVM_partial.Data => DataA_interface.Data;

    IData IVM.Data => Data;
}

public static class RunVM<T, VM>
    where T: class, IData
    where VM :class, IVM
{
    public static T RunMe(VM hi)
    {
        var vmA = (hi as VM);  //how to force-cast this to the VM type??!!
        return (T)vmA.Data; 
    }
}

class Program
{
    static void Main(string[] args)
    {
        VM_Partial partialData = new VM_Partial();

        var VMClass = new VM_Total(partialData);


        RunVM<DataFull, IVM_Total>.RunMe(VMClass);
        RunVM<DataPartial, IVM_partial>.RunMe(VMClass); //here it throws exception because I can't force cast the IVM to IVM_partial

    }



}

At the method RunVM<DataPartial, IVM_partial>.RunMe(VMClass);, I want it to return me the DataPartial object, which I know it's there in the object VMClass, but I cannot get it done.

I will get an InvalidCastException when I am at the RunMe method, because the parameter hi is always VMClass, and I can never get it to behave like IVM_partial class. In other words, I can't cast hi to a more basic interface IVM_partial.

How to cast hi to a more basic interface IVM_partial? Is it possible at all, and if not, why not?