The burden of establishing the existence of a valid and enforceable arbitration agreement includes proving that the party seeking to compel arbitration was a party to the agreement or had the right to enforce the arbitration agreement. In re Merrill Lynch Trust Co., 123 S.W.3d 549, 545-555 (Tex.App.-San Antonio 2003, orig. proceeding), mand. granted, 235 S.W.3d 217 (Tex.2007) (orig. proceeding) (per curiam). "Federal courts have recognized six theories, arising out of common principles of contract and agency law, that may bind nonsignatories to arbitration agreements: (1) incorporation by reference; (2) assumption; (3) agency; (4) alter ego; (5) equitable estoppel; and (6) third-party beneficiary." In re Kellogg Brown & Root, Inc., 166 S.W.3d 732, 739 (Tex. 2005).