Plan Orders remove PLSFX and PLAFX indicators

Hi Gurus

I have too many Plan Orders that are firmed and where both indicators PLSFX and PLAFX are flagged/selected.

I understand and tested that if only PLAFX is selected I can use COHV or MD12 and Remove/Delete the Fixing but this doesn't work if PLSFX is selected as well.

Can you please advise how I can proceed so at the end of the day I can "Un-Firmed" my Plan Orders?

Can I do it via one step or two steps, removing first PLSFX and subsequently PLAFX via COHV?

Is there a conventional way to do it without resorting to BAPI and/or individually doing each Planned Order? I have read several post where BAPI_PLANNEDORDER_CHANGE is recommended but I checked and I cannot use it.

I checked as well MRP Type and is all ok I believe this Planned Orders where firmed when doing availability check and by accident, the user selected the Firm Planned Orders tick box in that transaction. I might be wrong on this one but is my only theory so far

Thanks so much in advance

Roberto