Press and hold the MENU(3) button to enter the main menu.
Rotate the controller (6) to select the Reticle & Zeroing menu item and enter by briefly pressing the MENU(3) button – zeroed distances are displayed at the bottom.
Select a non-primary distance and enter the submenu for operating the distance with a brief press of the MENU(3) button.
Select Change Primary Distance item.
Press the MENU(3) button briefly.
Icon next to the selected distance confirms the change of primary distance.
There will also be a recalculation of corrections in clicks for other distances relative to the new primary distance.