Can we change absence policy if employee uses FMLA leave?

Q. If we have union contract and want to change the attendance policy to be able to get rid of all the people who take FMLA, OR approved disability, is it okay to change from past polices that have satisfactory dates to no satisfactory dates at all. We also want to skip counseling and warnings upfront and go straight to written warning on first offense if the person was on FMLA and the time ran out while he was out. Can I discipline that employee even if the past attendance was good as long as I discipline all employees the same way? – Anonymous, Indiana