Assume Mn is the n‐dimensional permutation module for the symmetric group Sn, and let Mn⊗k be its k‐fold tensor power. The partition algebra sans-serifPkfalse(nfalse) maps surjectively onto the centralizer algebra sans-serifEndSnfalse(Mn⊗kfalse) for all k,n∈double-struckZ⩾1 and isomorphically when n⩾2k. We describe the image of the surjection normalΦk,n:sans-serifPkfalse(nfalse)→sans-serifEndSnfalse(Mn⊗kfalse) explicitly in terms of the orbit basis of sans-serifPkfalse(nfalse) and show that when 2k>n the kernel of Φk,n is generated by a single essential idempotent ek,n, which is an orbit basis element. We obtain a presentation for sans-serifEndSnfalse(Mn⊗kfalse) by imposing one additional relation, sans-serifek,n=0, to a presentation of the partition algebra sans-serifPkfalse(nfalse) when 2k>n. As a consequence, we obtain the fundamental theorems of invariant theory for the symmetric group Sn. We show under the natural embedding of the partition algebra sans-serifPnfalse(nfalse) into sans-serifPkfalse(nfalse) for k⩾n that the essential idempotent en,n generates the kernel of Φk,n. Therefore, the relation sans-serifen,n=0 can replace sans-serifek,n=0 when k⩾n.