As an account administrator you can have several users in your system. They will be able to schedule events in your account.
If you want to remove the access to the system but keep that information [as opposed to entirely deleting them] you can go to “users”, find the user in question, click “edit” in the “actions” column, and uncheck “active” in their profile..
Note: an inactive user will be counted against the maximum number of users permitted in your account [usually one account administrator and 2 free account users per account].