Reproschema allows for changing responses at any state of the protocol execution. However, this does not behave the way it should in most cases and are related to conditional logic (isVis) and compute. It is also a complex process in that a change may only affect a few or no elements or many elements depending on the type of change.
A design document should be created for expected changes in flow. In addition there should be considerations for whether changes are allowed in previous activities or only in the current one.