There are various ways to remove a duplicate purchase ledger transaction (with detail) that has been posted:
Using Corrections:
Select the duplicate transaction.
Right-click and select Corrections.
Select the Delete icon to remove the transaction.
If this option isn't available then please use the following to balance the account:
Using a Credit Note:
Create a Credit Note with the reverse amount of the duplicate transaction.
The 2 transactions will then need to be allocated together.
Using adjustments:
Create an adjustment to Decrease or Increase the supplier balance
Make sure to Reference the details from the duplicate transaction is in the description to highlight what the adjustment is for.
Note: If there is a duplicate transaction entry which has no detail line showing for it (when expanded), then this will need to be corrected for you by Support, as this usually means that the original transaction has duplicated only it's "header line". In this event, the above methods would not resolve the issue, and therefore please raise a new case online and reference the title of this article and please include details of the transaction affected.