Yes it's entirely legal. Can an employer legally withdraw a prospective employee's job offer?In short, the answer is yes. Second step: Validate with the employer that the offer has been formally withdrawn. Revoking an employment offer is not illegal in most cases, but the decision should be given a full legal review before contacting the candidate. Be polite, don't make up reasons. Just tell them you regret to inform them that you can't take the position. If a job offer that you've already accepted has been rescinded, remain calm, advised career experts.