I have to do one of my co-assistant's evaluation today

Her six month probation recently ended and, as expected, payroll was asking me about her attendance, how she's been gone on days when she didn't have any PTO. Hate to do it, but I'm going to have to give her a poor rating on her attendance, but I'm going to try covering for her with payroll as much as I can. I'll just be honest and say she's been facing some adversity in her personal life (without disclosing any details, of course) that have forced her to take days off when she didn't have the PTO to do so, but her attendance has improved in recent weeks, which it has, and she's still considered a reliable and helpful addition to our team. Worst case scenario, HR will want to take disciplinary action and give her her first written warning, but I'm hoping they'll give her a pass this one time. We'll just see. I know it's necessary and all, but I never like doing this part of my job.