An invoice had to be changed so it was voided to allow access to SO-A to change the Sales Order.  A new invoice (new invoice #) was printed and posted.
 
Now another change needs to be made to the Sales Order.  SO-A says the new invoice has been printed but not posted so it will not allow additional changes to the SalesOrder.  The message says to go into SO-F, print the unposted invoice, then answer "No" when asked to mark the invoice as printed.  When I go into SO-F to print the unposted invoice, it shows me the graphical form name (BKSOF4.RTM), asks where I want it printed, then returns me to the menu as though I had cancelled out.
 
Does anyone know how to deal with this?

Thank you John.  Your answer worked in the main company.  Just to be sure I had it, I tried to replicate the procedure in my Test company.  
 
DBA tells me it "can't void invoice #2414 because there is an unposted invoice #2415 pending against that SO".  When I try to post #2415, it says "there are no printed , unposted invoices".  When I go back a step and try to print the supposed unposted invoice, it says "there are no sales orders for the chosen criteria".  I've tried all the Y/N combinations of Ship Date as Post Date, Print all released SO's, etc. and nothing works.  
 
I seem to have a phantom invoice that DBA won't let go of.  Any ideas on how to clear it?
 

I tried to re release the SO and rec'd the msg "SO was closed.  Do you want to reopen it?"  I said Y.  Went back to SO-A and opened and saved the SO.  Then SO-E to release the SO.  Then SO-F to print the unposted invoice.  DBA says "No SOs for the chosen criteria".  Checked SO-O-I , the "SO Released / Not Posted" report and it was empty.

In addition to my earlier post I just wanted to point out that we started out with the exact same problem, voided invoice, reprinted and posted a new one then we went back in to make another change to the 2nd generation invoice and got stuck in this loop.

I was excited to hear you had a suggestion to fix this.  I tried to do what you said but am still having the problem.  I am afraid that I tried too many things in Maintain Database before and after I read your response.  Do you know what files contain records relating to invoices that were generated from a particular SO?  Can I go to those files and delete the associated record in the files and get back to the starting point where I just have the SO in the system?
 
I realize this might just be wishful thinking!