Sole proprietorships are business entities that are tied to a single owner. The entity is considered a "pass-through" tax entity, which means that for the purposes of taxes, the profit earned by the sole proprietorship is considered to be earned by the owner directly. Additionally, the assets of the sole proprietorship are owned by the individual owner. Sole proprietorships do not need to meet state registration requirements, so transferring a sole proprietorship to another individual or company is fairly straightforward.
Create an inventory of the tangible and intangible assets of the company. Tangible assets include office supplies, automobiles, office space, software and any other specific assets you can identify. Intangible assets include intellectual property, patents, goodwill and any other valuable commodity your company has that does not have a physical form.
Apply a valuation to asset listed in your inventory. The valuation can be determined in a number of ways, but generally you should value the asset based on the asset's basis--how much you paid for it when you acquired it--minus any depreciation over the life of the asset.
Total the value of all the business's assets. This is the net worth of the sole proprietorship.
Prepare a purchase agreement that lists all of the company's assets and the valuations that you determined. The purchase agreement should explicitly state the amount of money the buyer is paying for the assets and the terms of the sale. This includes how long the buyer will pay if he is paying on installments and any rights that you retain or are transferring over the sole proprietorship's name or intellectual property.
Sign and date the purchasing agreement and have the buyer sign and date it. Because the purchase agreement is a simple contract between two consenting parties, it does not need to be notarized or witnessed, or filed with any state agency.