I had booked a 14 day Norway cruise out of Southhampton for Jun 2020 last month.
A week later had a general email solicitation from NCL with additional included options.
I rebooked with the next door cabin for the additional savings on excursions and called and cancelled my original reservation.
Had another general email this morning so investigated. Got a quote with the same perks as my 2nd reservation for $800 less.
Called NCL and asked if I had to cancel and rebook, The person applied the new lower price to my existing reservation.