An easement can be ended ('extinguished') through express 'release' by the person who uses it - that is, the owner of the dominant tenement. The easement is then removed from the register of both properties.
In the absence of an express release, the person who granted the easement (the owner of the servient tenement) can ask the court to extinguish the easement where the conduct of the dominant tenement's owner shows a clear intention to abandon it.
An easement cannot be terminated by the grantor unilaterally choosing to bring it to an end.