Short answer:
Just tell your provider to upgrade the secondary connection to a primary product.
Full answer:
Chorus classify services as Primary & Secondary, previously they have only permitted a single Primary service to be present at a time which has prevented multiple 1Gb products from being activated (the 1Gb Product only exists as a Primary service) however this restriction has been removed over the last few months and second Primary service can be ordered simply by submitting a Change order to replace the secondary service with primary product, as the existing service would sit there unused this would not cause any performance issues on the ONT.
Full Info:
https://sp.chorus.co.nz/product-update/multiple-primary-offers-single-ont

