DTW Stock with Serial Numbers

Hi all, I DTW'd some stock in through the GRPO template. I then AP'd the invoice. Due to some administrative issues I had to credit the Invoice thus reversing the stock. So the Serial Numbers are all reflecting as unavailable.

I need to re-import the stock with the same serial numbers and different costs. The DTW is giving me an error "(Serial Number) for item (Item Code) in line 1 already exists (in unique field)/Application defined or object defined error65171"

I realise that these serial numbers are already in the system, but if I manually capture these on the GRPO the the application asks me to confirm this already exists. There are almost 2000 items to capture. Please could someone advise if there is possibly a field on the DTW template (purchase delivery) I could populate that overides this error"