You don’t.  If you have an objection to being a member of the Union by virtue of your employment with the Employer, you can claim something called “Rand Formula Exemption”, for example, for moral, religious, or other reasons.  Contact us if this is what you’d like to do.  However, you would still be required to pay dues to the union same as all members, because you benefit from the collective agreement and enter the job with provisions and benefits and wages having been negotiated by the union for almost 100 years.  You inherit privileges other workers have paid for with their work, volunteer efforts, dues, service and struggle.  The most important of the protections you get as a unionized worker is a right to due process.  This doesn’t seem like a big deal – most of us take it for granted – but there is no obligation in the law for an employer to treat you in any particular way other than as provided for by the Employment Standards Code minimum legislation which provides for at will employment – meaning if you are a non-unionized employee, you can be terminated at any time, for any reason, or no reason at all, except for a reason prohibited in human rights legislation, OHS legislation and similar.  This has humourously been interpreted by some Employment lawyers as “you can’t be fired for being white, but you can be fired for driving a white car.”  In other words, the employer can’t fire you for given reason of race, gender, sexual orientation, etc., but can terminate you at will – and only have to pay you the minimum in lieu of notice severance, OR, provide you the notice and the opportunity to work the notice period.  Other exceptions apply should you seek Common Law Remedies, since the judges apply a different principle called “The Commonlaw of Master/Servant Relations” – and tend to award higher severance, but to access this, you have to sue.  There is no expedited process to a common law remedy.  A unionized employee has a right to “just cause” in discipline, and protections of the negotiated collective agreement.  That means that the worker who is a part of a union is actually collectively working under an agreement negotiated by the Union for the term of the agreement – and severing such employee from the Bargaining Unit requires the Employer to demonstrate, if needed to a third-party neutral arbitrator, that they have enough/sufficient/just cause or reason for why the discipline was given or termination affected.