Can an election bring positive change?
Sure. An election can bring positive change. It can also bring negative change. It can also bring both at the same time . . . or neither. It also will greatly depend on who is being elected, and it greatly depends on who is the recipient of any changes made by the elected official(s).
Being completely objective about politics is the closest thing to impossible that I can think of. It's why I refuse to talk about politics with my own family. I might think that the election of a certain candidate will bring about more positives than negatives, but a different person might believe that same candidate is the closest thing to the spawn of Satan himself.
Let's look at Lincoln as an example. Every history and government class that I have been in has revered Lincoln as the greatest president in history. Through that lens, it appears that everything that Lincoln did brought about positive change. Sure, it might have kicked off the civil war and caused crazy amounts of death, but overall his presidency strengthened the nation. On the other hand, Lincoln was universally detested in the South. Everything that he did supposedly brought about negative change.
To go back to your question, yes, election can cause positive change. It just depends on who you ask.