How do you differentiate change Order to a Variation Order?

As far as my working experience, there is no difference between those two wordings. Anyway, in some countries/ Projects, it is used as Variation Orders (VO), and others as Change Orders (CO).

In either case, the change (Addition, Omission, alteration) happened to the original contract is counted. Upon the request of the Contractor or the Identification of such change by the Consultant/ Employer, the VO/CO shall be issued by the Consultant/ Employer.