I used to have an agenda which we'd use for our HACCP review but also for any HACCP meeting which was out of cycle (just to make sure everything was covered). I can't remember the exact wording but I think I had a question on there to prompt review of verification activities after any change. So that then became an agenda discussion point and I could record it had been discussed and the outcome of that discussion. It helped with audit compliance but also helped make sure we were considering it.
In reality it depends a lot on what the change is. For example, a move to an automated palletiser in a low risk area will change your flow but it will be unlikely to change your EMP programme. A movement of one chiller into another meaning your movements of ingredients changes strangely might not change your process flow but probably would change your EMP if the different ingredients have different intrinsic microbiological risk (e.g. fresh washed leaf vs. fully cooked pasta).
Ultimately ANY change in HACCP should at least prompt a review of your verification activities (not just environmental monitoring) and that could include process flow diagram changes but also changes too subtle to make a difference to your process flow.
