The Collaborative International Dictionary of English v.0.48:

Accommodator \Ac*com"mo*da`tor\, n.
   He who, or that which, accommodates. --Warburton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

accommodator
    n 1: someone who performs a service or does a favor [syn:
         obliger, accommodator]