** how to do it **

 

+ at N Z Prime Minister John Keys' direction an open contest for a new flag was launched, its first step by the review panel being a longlist selection of 40 designs (from over 10,000 design entries) ... Done

+ from these longlist entries the review panel then selects a final FOUR shortlisted designs which were offered (Sep 2015) in a national binding referendum to rank them, to produce a winning design

+ in March 2016 referendum to confirm replacement of the flag design

... not really so complex or burdensome is it, Australia ??

Note that after NZ makes this change, only Tuvalu and Australia retain a colonial ensign as their flag!