Tex. Water Comm’n, 790 S.W.2d 299, 301 (Tex.1990) (“A statute is presumed to have been enacted by the legislature with complete knowledge of the existing law and with reference to it.”). Had the legislature not intended to limit the term “grandparent” to individuals related within the third degree by consanguinity, it would not have needed to include the word, “another.” Instead, the legislature could have phrased the section to read, “a grandparent or relative of the child related within the third degree by consanguinity.” See Tex. Workers’ Comp. Ins. Fund, 35 S.W.3d at 593. Because there is no evidence that the Harveys were related to CAIH within three degrees of consanguinity, they lack standing under section 102.004(a). See Tex. Fam.Code Ann. § 102.004(a); Derzapf 219 S.W.3d at 328 (<HOLDING>); A.M.S, 277 S.W.3d at 98-99 (holding that
holding that stepgrandfather who was neither a biological nor an adoptive grandparent lacked standing to seek access to stepgrandchildren holding that a party that was neither a purchaser nor a seller of the securities involved lacked standing to seek injunctive relief under the federal counterpart to  8617 holding that biological grandparents were statutory strangers to children following their adoption by stepfather statute authorizing grandparent visitation violated parents constitutional right to privacy holding that the prison physician lacked standing to raise the prisoners rights of access to the courts holding that plaintiffs lacked standing to sue