From the ticketmaster.com webpage: "Heather Nova's management has postponed the album release and also the Lucerne gig on July 26th, KKL Konzertsaal. The new gig takes place on October 5th, 20h, KKL Luzernersaal. Tickets are still valid for the seated Luzernersaal balcony on October 5th."

Update: In contrast to what ticketmaster.com writes, tickets are definitely returnable ! as the Blue Balls organizers confirmed once again on the phone. The ticket seller got informed in the meantime ! (edited by Chris91275)

Note: There are now two ticket categories sold:
1) seated category on the balcony, 69 CHF
2) standing category, 59 CHF