How do I remove vacuum lines on Ford Focus?

I have a 2000 Ford Focus LE with 2.0L DOHC engine. How do I remove the vacuum lines running to the EVAP Canister Purge Valve on the firewall? They are held on with a plastic locking collar but I don't know how to get them off without breaking them.How do I remove vacuum lines on Ford Focus?I know some fuel lines require a special tool. See image below