変更してみろ makes sense but it might not be suitable for what you want to write. It is an imperative phrase for telling someone to 'try to change (something)', which may or may not be the meaning you want.
変更 (へんこう) + する combination is a transitive verb. If you want to mean 'change' as in someone himself changing, then this is probably not the correct verb. In this situation I would normally think of an intransitive verb like 変わる (かわる) or 変化する (へんかする). I'm not completely sure about this though.
して is the て-form of する. So 変更して is the て-form of 変更する.
みる means 'try' when it is used after the て-form of a verb.
みろ is a strong imperative form of みる and sounds very blunt. You need to be careful using this form unless you want to sound rude and offensive. It may not be rude at all in the context you are writing this phrase for. みて is a less blunt imperative form, or can make it more polite by using みてください for 'please try ...'
Now, if you wanted to actually say 'dare', there is an adverb you could use: 敢えて (usually written only in kana, あえて).
So you could write あえて変化する, but this may be completely wrong depending on your context. Some form of ~てみる is probably a safer thing to stick with than to use あえて, but I would think about which verb is the most suitable one to use for 'change'.
(I think I write too much... These are just my views and may be completely incorrect.) ^^;
June 27, 2015 at 10:40am