Incorrect transaction type

WE have incorrectly used the transaction type as acq(100) when they should have used 300 for a transfer. What should I do to correct it.

This entry is for conversion fo warehowse stock to capital spare... and they are supposed to book it as a transfer, but it is booked as an acq.

Can anyone tell me what is the right way to correct it

I can not even reverse it as its past that month.

.

Any clarification is appreciated.