If you wanted to automate the reversing process in code, you could use InventJournalCopy something like this (look at InventJournalCopy::main(..) for usage hints)
InventJournalCopy copy = InventJournalCopy::construct();
copy.getLast();
copy.parmJournalIdFrom( journalNumHere );
copy.run();
This is not tested code. Use at your own risk.
InventJournalCopy copy = InventJournalCopy::construct();
copy.getLast();
copy.parmJournalIdFrom( journalNumHere );
copy.run();
This is not tested code. Use at your own risk.