Maybe try:
ShippingConfirmation*.* > Completed*.*
but I'm not sure since it might not understand the wildcards.
ShippingConfirmation*.* > Completed*.*
but I'm not sure since it might not understand the wildcards.
For /F "Tokens=1* Delims=_" %%I In ('Dir /B ShippingConfirmation*.txt') Do Rename "%%I_%%J" "Completed.%%J"