The Collaborative International Dictionary of English v.0.48:
Reconfirm \Re`con*firm"\ (r[=e]`k[o^]n*f[~e]rm"), v. t. [Pref. re- + confirm: cf. F. reconfirmer.] To confirm anew. --Clarendon. [1913 Webster]WordNet (r) 3.0 (2006):
reconfirm v 1: confirm again; "You must reconfirm your flight reservations"