March 09, 2018 21:34 Updated Follow Please fill out this form and submit it to INPRS. Our address and fax number are on the form. Related articles If I participate in the DROP, retire on my chosen DROP retirement date, and choose the DROP benefit, how will the DROP benefit and my monthly retirement benefit be calculated? How do I begin participating in the DROP? If I wish to retire on my DROP retirement date, how do I file for benefits? How can I get an estimate of my PERF retirement benefit? At what age should I retire?