JAR 1year Validation

[the road atlas]

I am following up a particular comment on another thread regarding getting a 12 month JAR license "validation" from a particular countries CAA. “In theory, and according to the JARs, the validation is to allow you to fly for a year while you get the JAR license.”

Can you tell me if a company has to do this on your behalf, do you need a job offer first? Or can I apply for one with the understanding I 'should' be through my JAR licnese within the year? Can you guide me to the relevant JAR rule?

Thanks
atlas