Transactions in the NetCommunity plugin can be deleted manually. You want to know what happens if a transaction is deleted.
If a transaction is deleted in the plug-in, this does not change the registrant being charged because registrant is already charged at the time of transaction, assuming it was fee related. Therefore, deleting the transaction will only cause you to lose the data or gift information associated to the transaction. The transaction will not appear in a gift batch because it was not processed.