Michelline said:
Example their work permit is in food store, after a year she/ he quit the job. And now he/she working at other employer without work permit for employer
If the work permit has conditions specifying the employer name, this is a restricted (aka "closed") work permit and the work authorization is only for the employer named in the WP.
If the holder of this WP quits this job, and goes on to work for
another employer - then he/she does not have authorization to work for the new employer. They cannot use the old/restricted WP to work for another employer.
Unless she/he is a holder of an open work permit (no conditions specified on the workpermit, no employer listed as part of the conditions) - he/she is currently working without authorization.
.../atb