1) Create modification.
2) Copy exchange details, and then modify amount to zero while specifying fiscal year and period (Example: FY 2023 and Pd 13.)
3) Paste exchange details into new line on that tab, and then specify the fiscal year and period as FY 2024 and Pd 2 (i.e., current period).
4) On second party accounting, copy every line from the first exchange detail line to the second, and then specify those lines as FY 2024 and Pd 2 (i.e., current period).
5) Switch back to lines associated with first exchange detail line, and then zero out the amount while specifying fiscal year and period as FY 2023 and Pd 13.
6) Since we are still in yearend closeout, make sure to specify the Header as FY 2024 and Pd 2 (i.e., current period).
7) From there you should be able to validate and submit. Make sure to have someone else check your posting lines to see that the opposite is happening on the first group of $0 lines (i.e., positive amount on 1st party; negative amount on 2nd party), whereas the intended posting happens on the second group of lines (i.e., negative amount on 1st party; positive amount on 2nd party).
If everything checks out, that should back out the accounting activity in old year and apply it in new year.