I prefer 1, actually. Change is an inherently passive thing, you can't stop change, change happens for its own sake. It's perfectly fine to say "standards have changed" because standards are always changing.
It's like "events have happened." The events themselves have no power to happen or not. There are plenty of fictional events that never happened except in books, and the event itself can't change that. Happening is an agent, it is the bringing into reality itself.
That said, 2 is grammatical, but less poetic. It calls to mind that there is a process to change standards, and that process has happened, instead of just saying that things are different now, and it doesn't matter why.
This is a silly question. It asks one to do something that can't be done.
The sentence
- I must go and look for my brothers.
is Intransitive, but Passive can only apply to a Transitive clause.
The Passive rule promotes the direct object to subject, demotes the old subject to an optional object of by, and adds the auxiliary verb be before the past participle form of the main transitive verb. Like this:
- Marie shot my cousin. == Passive => My cousin was shot (by Marie).
But if the clause isn't transitive, there isn't a direct object to promote, and other noun phrases don't usually work.
- Mary slept all day. but not *All day was slept (by Mary).
Sometimes prepositional objects can be passivized, if the preposition is one that makes a transitive verb out of an intransitive one, like look (at) or listen (to)
- We must look at/listen to that again. == Passive => That must be looked at/listened to again.
But that's rarely the case, so most prepositions after verbs don't mark direct objects. And without a direct object, Passive is impossible.
The real solution is to get a new textbook that actually describes English, instead of something like English.
Best Answer
Rewording your sentence very slightly, I believe that what you intend to say is:
That would be the active version of this sentence using the verb shift transitively, with emphasis becoming the object. In that case, to structure the sentence as you have it, you would want to use the passive voice, so you would write:
If you instead use the active voice, you are using shift intransitively, and your sentence would read:
In this case, you are still using the so...that construct to communicate cause and effect, and because of that, you are still communicating the same message to your audience. The difference would be in the emphasis on emphasis - whether it be the modifications as the actor causing the shift (transitive), or the emphasis itself changing (intransitive), along the lines of what eques mentioned in his comment.