You can make a Pick Ticket Inactive. The Inactive Status is halfway to delete and the record will no longer show unless you specifically look for it.
Select the Pick Ticket either from Sales Order list-view...
..Or inside the Order Tracker
Untick [Active]
[Save] and [Close]
The Pick Ticket is now inactive and it is displayed with a line through it on the Order Tracker
It will no longer show on the list view (unless you decide to include inactive records)
The product quantities will be released back to your CLOSING stock and available for you to pick for other sales orders.