Welcome Caleb!
Data Management Tool to the rescue! The DMT is a module you purchase from Epicor that allows you to mass update pretty much anything in Epicor. It is fast, and relatively easy to use.
If you don’t have DMT (and can’t get it), the work needed to automate this entry would probably be slower than manually updating each record. However, if you still want to go the automation route, you have to first determine which methods are being used when you manually update the req by date. Do this by running a trace and parsing it with Jose’s handy tool. Trace Helper Utility for Epicor ERP 10 - ERP 10 - Epicor User Help Forum (epiusers.help)
Once you know the methods, you can begin to build a BPM that replicates the same methods. This is entirely doable, but the process will be slow if this is your first time. If you have the ability, I highly recommend getting the DMT for your company.