You could try looking at classic.checkmytrip.com, under the e-ticket tab you may find the fare basis there, which may help.

It may well vary if it is a Morocco issued ticket, each sales point seems to have its own rules about this, and generally speaking it is best to do a screen print at the time of booking to retain the change conditions.

But with that caveat in mind, it would not surprise me if there was a change fee and reprice on an O bucket, perhaps €80 or so, and just a refund of taxes if cancelled (and from Morocco we can assume that will be close to a zero refund). Best done over the telephone since I cannot believe this would be easy to arrange in CMB airport!

I'm not sure what would hold you back from calling to check this, given GGL status.