This is how it works in Sweden: https://www.unionen.se/in-english/notice-to-termination

"Even if an employer does not have a collective agreement, they must negotiate major changes to working and employment conditions of employees who are members of a trade union as if the employer had a collective agreement."

Negotiations include getting the lists of positions that will be terminated, number of employees affected, new positions that may be opened during a reorganization, etc.