Yes, you are allowed to change employers.
Your employer cannot penalizeor deport you for looking for another job. However, your work permit may only allow you to work for your current employer. Before accepting new employment, remember that your new employer will have to get permission from the Government of Canada to hire you as a temporary foreign worker. You will also need to apply for a new work permit before changing jobs. Workers under the Seasonal Agricultural Workers Program do not need to get a new work permit if they change employers.