Hey @Monica G., I've seen it done many ways.
As others above have, I will also state that this is not legal advice nor am I advising you as a licensed agent.
That said, what you decide to tell the listing agent is entirely up to you. If you're not using a buyer's agent to represent you as the "buyer," you might consider enlisting the help of one. You might be able to find someone to do this in return for a flat fee paid from the buyer's agent commission at closing, the remainder of the buyer's agent commission being paid to you or the end buyer in the form of a commission rebate.
As for your original question, I've seen it done many ways, but the simplest and most popular way is to add "and / or assigns" after your or the buyer's name on the original contract with the seller.
If there's an existing relationship with the seller, i.e. you're already in contact with them and / or they know your intent for the property (wholesaling) you're in a pretty strong position. The listing agent must act in the best interest of their client (the seller), but the decision as to what to do with the property ultimately lies with the seller.
Be as upfront and honest as possible with the seller. Contract the property using the correct form(s) at a price that leaves you room to make your assignment fee. You'll obviously need an assignment form that will convey your interest in the property to the end buyer. You'll also want to make sure your end buyer has the financial wherewithal to actually close on the property. It's imperative that you take responsibility for the property closing, whether you actually intend on closing yourself or not.
You protect yourself with the "and / or assigns" and by negotiating and paying for an option period during which you may terminate the contract at any time and for any reason. (You should be putting up earnest money with the title company as well.)
Highly recommend you seek the assistance of a local agent / attorney / title company / wholesaler to help walk you through the entire process in-person. You'll need an investor-friendly agent, who may even have a buyer for you. An investor-friendly real estate attorney who will actually be familiar with what you're trying to do. An investor-friendly title company who will actually close an assignment (some don't). And, an experienced wholesaler would likely be willing to hold your hand through the entire process in exchange for half of the assignment fee. (Better to have half of something than all of nothing.)
Best of luck!
P.S. - Commissions are typically paid from the seller's proceeds at closing and are dictated by the listing agreement. Typically not your concern as a wholesaler...
