g(NH3)2Cl + 2HNO3 = AgCl + 2NH4NO3
So, by protonating ammonia to ammonium, ammonium will be eliminated from the complex. It's hardly surprising that ammonium has different binding properties to ammonia but I don't see how that is a property that is unique to a 'dative' bond. You can also eliminate H2O from ethanol by protonating OH to form water. I don't see the fundamental difference.
As far as I can see, the concept of dative bonds are useful for accounting purposes and for predicting good leaving groups but the bonds themselves are fundamentally the same. If someone can give an orbital description or similar to explain the difference I'd be happy to hear about it.
Significantly, none of my three textbooks on inorganic chemistry even carry the term 'dative bond' in the index.