RECO doesn't leave the wording to you — it hands you the script, the form, and the list of things you are flatly prohibited from doing.
Short answer
Before you provide any assistance, RECO requires you to give a self-represented party the RECO Information Guide and the Information and Disclosure to Self-represented Party form, and to walk them through specific messaging: that you represent your client, not them, and cannot give them any services, opinions, or advice. You then need best efforts to get written acknowledgement that they received and understood it.
RECO Bulletin 2.4 sets out the actual language RECO expects you to communicate: “I am representing my client and my client's best interests. I do not represent you or your best interests. I cannot provide you with any services, opinions, or advice. Any assistance I might provide to you is to benefit my client and their interests. Any information…that you share with me will be shared with my client.” That last line is the one self-represented buyers most often forget mid-negotiation, and worth repeating out loud, not just burying in the form.
The bulletin is equally specific about the limits: you cannot provide “services, opinions, or advice to a self-represented party in respect of a trade, including an opinion or advice on the price, terms, or clauses to include in an offer.” Any assistance you do give has to serve your own client's interests — not the self-represented party's — and must contain no opinions or advice to them at all.
The Information and Disclosure to Self-represented Party form must be given and walked through “before any assistance” is provided, and RECO expects “best efforts to obtain acknowledgement” that the information was received, with a copy given to the party. Skipping this because a showing feels informal is exactly how the old customer-relationship habit creeps back in — and it's also how an unscripted, helpful answer to a casual question tips into an implied representation agreement you never intended to create. See how one buyer at the door tested this line in a real case file.
A 30-minute call is enough to tell you whether your process holds up.