Tool axis changes are more common to 3-axis parts, or for changing the direction a hole might be machined from.
To change the tool axis, click the Tool axis drop-down menu and choose from the available setups.
Note - there may be only a single valid choice of tool axes.
Note - when a change is made to Tool axis, the default behaviour will be to lock the field. This will prevent changes to other edit fields from changing the Tool axis field. Select the lock button to unlock the field.