BUENOS AIRES/NEW YORK (Reuters) – Citigroup Inc (C.N) will not appeal a U.S. judge’s ruling that it cannot process an Argentine sovereign debt payment if he helps the bank exit its custody business in the default-hit country as swiftly as possible, its lawyer said on Wednesday. Citigroup’s stance paves the way for a showdown with leftist President Cristina Fernandez’s government, which is demanding the bank handle a March 31 payment or else risk sanctions, including the possible loss of its operating license.