A method includes: sending a transmission instruction to send status information indicating a state of an image formation apparatus; receiving a status information in response to the transmission instruction; determining, based on the status information, whether to permit a lock instruction to be sent causing the image formation apparatus to shift to a locked state in which only image formation instructed by a first external apparatus is executable; sending the lock instruction when the lock instruction is permitted to be sent; causing the image formation apparatus to shift to the locked state in accordance with the sent lock instruction; sending an unlock instruction to cancel the locked state; and causing the image formation apparatus to shift to an unlocked state in accordance with the sent unlock instruction. The lock instruction is permitted to be sent when the image formation apparatus is determined to not be in the locked state.