Change property type using reflection-Collection of common programming errors

I have a decimal Value property in my domain class:

public class Domain
{
   public decimal Value {get;set}
}

I need to assign that Value property with two database values:

obj1.Value = decimal.Parse(reader["Value"].ToString());
obj2.Value = decimal.Parse(reader["Value2"].ToString());

Than i have a comparer method wich compare these two properties:

public void Compare(List Domains)
{
     //get properties with reflection

     //if the properties values are different i need to set a 'string' value [DIFFERENT]           to it.       
     prop.SetValue(comparableObj, "[DIFFERENT]", null);
}

Is it possible to do?