Help! Can my teacher edit the reference if I still haven't submitted

If you are applying through your school, your school cannot send the reference separately. They have to wait until you have paid and submitted your application - it then goes to your school's UCAS person to complete the reference and add your predicted grades. They then send it to UCAS.
If its still with your school, and they havn't actually submitted it to UCAS yet, they can still tweak the reference. If its already gone to UCAS, no-one can make any changes and your school needs to email each Uni's Admissions Office to tell them that your school doesnt offer FM.