I have asked these tenants to leavse since November and they are still there. I went back several times to them and they still there. I dont know how to get them out. Other than the eviction proceedings, can I change the locks and have them call the police to get their stuff out?
Based on the facts in your question as presented, it seems like the only option would be for the landlord to commence an eviction proceeding, especially if these are residential tenants. Aside from opening oneself to liability for a wrongful eviction, the landlord could also be held liable if there is any damage to the tenants' property (during the time they've been locked out).
You should retain an attorney and commence a housing court proceeding.