Warriors fight all the better under the stern gaze of their General, taking heart from their noble presence (or perhaps fearing their anger more than the blades of the enemy). Providing that the General is not fleeing, all friendly units within 12" may use their Leadership instead of their own (so rally your General first), unless specified (such as having to use their unmodified Leadership).
If your General has a Line of Sight value of 5 or more, then the range of their Inspiring Presence ability is increased by 6".
If a unit taking a Leadership test has a modifier to its Leadership, this modifier still applies if the unit uses the General’s Leadership.
If a unit is Steadfast, it may use the Leadership of the General for Break tests if it is higher than their own Leadership after applying all negative modifiers from combat resolution. Otherwise, they will use their own Leadership.
For example, a Steadfast unit with Leadership 7 has lost the combat by 1 but is within the Inspiring Presence range of the General who has Leadership 9. In this case, the unit can use the Generals Leadership value and will test on Leadership 8. However, if they instead had lost the combat by 3, the unit will test on their own Leadership of 7, as this would be higher than using the General's Leadership value of 6 after combat resolution modifiers.