There are three kinds of COMPs in Modern Irish: go 'that,' aL (direct relative marker), and aN (indirect relative marker). McCloskey (2002) shows that the COMP alternation allows five patterns, when there are two positions for COMPs: (aL, aL, t), (aN, go, it), (aN, aN, it), (aL, aN, it), and (aN, aL, t), where t is a trace, and it is a resumptive pronoun. In this paper, we present the sixth pattern of COMP alternation (aL, go, it), which has not been extensively dealt with in the literature. We propose that this pattern suggests that aL and go are in an agreement relation, which forces go to function as aN, and discuss its implications for the theory of chains.