WordNet sense 1 (willing to adjust to differences in order to obtain agreement):

cooperative

WordNet sense 2 (not involving competition or competitiveness):

noncompetitive

WordNet sense 3 (tending to reconcile or accommodate; bringing into harmony):

reconciling

WordNet sense 4 (having a capacity for adaptation):

adaptive, adaptative

WordNet sense 5 (helpful in bringing about a harmonious adaptation):

accommodating