I ran into this issue recently when I changed the order of certain "Pet Info" questions and added new ones after updating my service agreements and requiring more information for clients regarding behavioral histories. After doing so, when looking at established client profiles, I noticed that the existing answers did not remain with the original question box. I also deleted a few questions that I used to ask, because those are now in separate intake forms that I use for Overnight Sitting.
When I deleted them (used that box for a different question) those changes applied to profiles that had been filled out previously, rather than being applied to new clients filling out My Info and Pet Info for the first time.
For example, one of my new questions was something along the lines of "What kind of altering did your dog undergo, if you answered "Yes" to the above?" and the answers for many clients were things like "No, they've never bitten" because that field used to be a behavioral history question. Essentially, the questions changed locations, but the answers did not match up with previous intake questions.
I think a system that retains old Info questionnaires and their original answers would be best, and when updated on the admin end, it only applies to new client intakes so it doesn't affect established accounts. Alternatively, it could give a message to my existing clients that says something like, "Kailey has added a new field for Pet Info, please review now before requesting services" so they can review their answer to the question and make sure it's still fitting for the new one, or review an entirely new intake question that I've created and answer it, depending on if it's required or optional. This might also be optional, because the question may not be relevant to established clients and only be something I want to ask new ones.
I hope this makes sense!