What tactics did labor unions use to try to change working conditions?

When workers strike to protest unfair labor practices by your company, they retain their employee status and their right to be reinstated when the strike ends. Temporary workers hired during the strike will be terminated at the end of the strike. If a striker finds full-time employment during the strike, he's not entitled to reinstatement. If strikers engage in any unfair practices, including threatening workers who cross the picket line or acts of violence, they'll lose their right to employment when the strike ends. Workers on an economic strike may attempt to convert it to an unfair labor practices strike if they could prove, for example, that your company wasn't negotiating in good faith. If the economic strike can be converted, then the striking workers retain their job security.