Rather than sending a memo to the junior, your company needs to develop a process where official communication is sent to the seniors. Therefore, in this case, the memo should be addressed to the superior and not the newly joined person. The rough draft of the email could be as follows:
Subject: Performance Evaluation on Completion of Probation
1. This is to inform you that Mr./Ms. __________ (name of the employee) bearing Employee No. ________ joined our organization on __________ (date). They have completed their probation on __________ (date) and are due for their first review.
2. You are requested to conduct their performance review under the provisions of paragraph No. ____, Clause No. ______ of the Policy on Recruitment or Policy on Performance Evaluation (if the process is online, then you may give reference accordingly) and send the report, duly completed, by _______ (date). Please adhere to the timeline to avoid unpleasant reminders from this office. Before conducting the performance review, please inform them in advance with a sufficient time gap of when the performance review will be conducted, where it will be conducted, and whether any materials they need to provide in support of their performance.
3. For Mr./Ms. _________: Offer your necessary support to __________ (name of the superior) for the smooth execution of the evaluation process.
Thanks,
Hope this suffices your purpose. You may make necessary amendments wherever necessary.
Thanks,
Dinesh Divekar