Author with same surname - removing first-initial in in-text citation

I have 2 authors with the same surname and different initials.Publications dates are different.  The in-text citations are showing surname, first-initial. How can I exclude the initial from the in-text citation?

The inclusion of the initial is often required by the publishers in instructions – but you can override this usually correct behaviour.  See http://endnote.com/kb/82224 for complete instructions – remember to save as and to change the output style to the newly named one, in the DOCUMENT (not in Endnote) to the new output style.