After several airlines recently made headlines for duct-taping unruly passengers to their seats, United Airlines is reminding its employees that it doesn’t endorse the tactic.

In an internal memo sent to employees and obtained by NBC News on Friday, United warned its flight crew never to use duct tape when restraining unruly passengers.

“Please remember that there are designated items onboard that may be used in difficult situations, and alternative measures such as tape should never be used,” John Slater, senior vice president of inflight services, told United’s staff.

“As you’ve likely seen, a few airlines have recently made news about the way they’ve handled situations onboard,” Slater added, reminding employees to de-escalate “difficult situations calmly,” including “discussing the situation with the Captain, Customer Service Representative and Ground Security Coordinator”.