So how exactly do you reopen the module then in Sage 100?

You just change the current period in the settings.  It's by module, but you have to set GL back as well or it will post to the current GL period.  So if you need to do something through Sales Order.  You have to set Sales Order to the period, A/R to the period, IM to the period, and GL to the period.  

When you are finished, you should do period ends to bring all the modules back up to current, or whatever you have them at now... just like you would normally.  For example: Sales Order Period End, AR Period End, Im Period End, GL Period End, and then through them again in the same order over and over until back to current

It's many years later and I was just curious if everyone still advises that if they have to reopen a closed period for a module other than the GL if you recommend still doing period ends to bring the modules back up to current. Is that step still necessary with current supported versions of Sage 100?

It's many years later and I was just curious if everyone still advises that if they have to reopen a closed period for a module other than the GL if you recommend still doing period ends to bring the modules back up to current. Is that step still necessary with current supported versions of Sage 100?

I still recommend the user process a formal Period End when they have finished with a reopened module.  Probably not needed, I like the period end close activity in the Activity Log, personally. 

100% run period end to change fiscal years... and we recommend it normally for regular period ends too.

Edit:

This does not apply to PR apparently... per Linda's post below.

One thing to consider is what period end and year end processing does.   If you go to Help and search on period end you will find a A/R Period End Processing, A/P Period End Processing, for each module.  These help topics each list what processes are run when the period end processing is run.  For example, in Payroll, the time off values are moved to the next period, year end processing clears ytd amounts for deductions, etc.  You would not want to rerun these processes with current year entries.

Thanks all. Always appreciate everyone taking the time to respond!