After digging around for awhile I found this (Scroll to the bottom and open Terms and conditions!!!)
https://www.ncl.com/specialty-dining-package/faq
...In part:
Specialty Dining Packages (SDP) are available online for pre-sale or onboard during the first two days of the voyage. SDP is not available on 1 and 2-day sailings; On 3-day sailings, SDP is for sale on day 1 only. No refunds available if not all meals are used. SDPs are personal (per person, e.g., 2 guests cannot share 1 SDP meal) and non-transferable (guests cannot give their SDP meals to someone else).