rubyrigz
There certainly are numerous operator options on ACARS packages, and the like. However, what we've been talking about is standard. It is part of the FMC/CDU from Boeing/Honeywell. There is one active route, and one 'backup' which can be used for the reasons mentioned.
What is in the inactive route will not be shared via ACARS, regardless of what operator options are chosen.
Jug:
In a word, yes. Or said route could be manually flown, or flown in basic modes. I'm not sure what your point is.
In summary, two flight plans can be loaded in to the FMS. One is active, the other isn't. The inactive route can contain anything - a diversion, an escape route, a mirror image of the active route, a modified version of the active route, or something completely irrelevant. To activate it, it's just short keystroke sequence.
What is in the inactive route is not displayed to ATC in any way. There's a good reason for that, as many of us like to make many modifications to it en-route - particularly over high ground.