Your wording is a little confusing so forgive me if I misunderstand, but it sounds like what you are talking about is illegal. It sounds like you're talking about signing a contract with the seller to buy a house for let's say $200k, then going to the buyer and selling them the same house for $210k. You can not do that because at this point you do not own the house. You can't sell something you don't own.
Your legal options as a wholesaler are:
- Buy the house. The seller sells you the house for $200k, when you close you legally own the house. You can then resell the house to your end buyer for $210k. You can set it up so that all this happens the same day; that's a double close. You close with the seller in one room, then walk into another room with your buyer. You have to buy the house with your own money.
- Sell the contract, not the house. Sign a contract with your seller agreeing to buy their house for $200k. Then assign that contract to your end buyer for $10k. Your buyer pays $10k to purchase the contract from you; that's contract assignment. They are not buying the house from you. That buyer purchases the house directly from the seller for $200k, the same amount that's on the original contract.