For B&W printers, click Properties > Finishing > uncheck Print on Both Sides
For MFPs, click Properties and uncheck Duplex (to reset, check Duplex and select Open to Left)
When printing from a browser, access the preferences settings in the Print window (click on the arrow sign next to the printer name) and uncheck the Two-Sided box
When printing from an MS Office application or Acrobat Reader, access the preferences settings in the Print window (click on the arrow sign next to the printer name), change Copies & Pages (third menu line from the top) to Layout, and set Two-Sided to OFF (to reset, change Two-Sided to Long-Edge Binding).