Amendments to tender evaluation criteria after pre-qualification
What process should be followed if you need to change evaluation criteria after PQQ stage?
Yes I agree with Michael. If you've already published details on the evaluation criteria then stop and restart. The time this takes will be a lot less than if you're challenged and end up in court.
I am assuming you are running an OJEU tender. My advice would be to stop the process and re-start it. It's not clear how you are amending the evaluation criteria, but it would be very difficult to demonstrate how this would not be interpreted as distorting competition given amendments would materially effect the outcome of the process. You may well annoy the bidders already involved, but you will save yourself the risk of a legal challenge down the line by doing so.