Don't do this in unit testing. Sure, you can but you really shouldn't. If Name has a private setter, and you have access to the code for that class, then it should be set inside the class it belongs.
Instead, identify where the property is being set and perform assignment there. If the name is coming from a database or file, for example, then inject that dependency and mock the part of that dependency that returns the name.
Or... mock the object.
Let the class worry about its internals. Setting the name could trigger some other processes to run. Purely as a demonstration for reflection, however, no problem.