You can only not compete with or not solicit a former employer's clients if signed a noncompetition or nonsolicitation agreement; in the U.S., employees may compete with former employers in the absence of some agreement to not compete. You can't solicit or work for this employer's clients while working for them, or try to get the client to leave your employer for you. That is because since taking work from your employer while working for them could easily be seen as a form of misappropriate or theft--using their customer list or contacts for your benefit, for example--and so could result in you being liable to the employer. So save this for if and when you job is phased out.