The article outlines the steps to batch edit sales order headers. Please ensure that SO's are in an editable status when following these steps.
FOLLOW STEPS BELOW:
1. In the Navigation Screen, Select Sales -> Sales Orders
2. Use search filters to help find the appropriate Sales Orders
3. Select Sales Orders you want to edit (Tip: Hold Ctrl and click to pick individual items one by one, or hold Shift and click to grab everything between the first and last item clicked.)
4. Right-click and press 'Edit Values'
5. Enter Details and press "OK"
NB. For a quick tutorial watch below