If the Rally Leader decided to cancel a Rally, he can do so both before and after the rally march starts. If the Rally is cancelled before the march starts, the units participating in it will remain inside the Leader’s Base as reinforcements. If it is cancelled after the rally march starts, the units are sent back to all players involved in that rally.
If the Rally Leader leaves or is kicked out of the alliance, the Rally will be canceled and all the units will be sent back to their owners. if a player who sent troops to a rally, is kicked, the troops will be removed from the rally and sent back to his base.
A player is not able to cancel a rally against him, if he leaves the alliance. However, he can shield at any time before the attack and the rally will be canceled.