I don't think those words have the same meaning. I mean, you can technically ask someone to consensually shackle you, but that's different. Of course, the doc does say "retract back to shackled mode", so what do I know..
You can shackle her depending on how you talked with her in the start.
There are 2 shackled modes,
Shackled(Sub)
Shackled(Cons)
And there is 1 unshackled mode,
Unshackled(Dom)
As far as i read the docs that's what i am led to believe and as nonesuch said, you can change her personality afterwards(got no idea how, guess we will find out xD)[I am kidding i do have an idea how, i did read all the docs ya know].