Tex. Tax Code § 151.024

If the comptroller determines that it is necessary for the efficient administration of this chapter to regard a salesman, representative, peddler, or canvasser as the agent of a dealer, distributor, supervisor, or employer under whom he operates or from whom he obtains the tangible personal property that he sells, whether or not the sale is made in his own behalf or for the dealer, distributor, supervisor, or employer, the comptroller may so regard the salesman, representative, peddler, or canvasser, and may regard the dealer, distributor, supervisor, or employer as a retailer or seller for the purpose of this chapter.