Dallas Green informed the rest of the band of his intention to leave Alexisonfire in 2010. Green agreed not to announce his departure until the rest of the band decided on their future plans. On February 14, 2011, on their official Twitter page, Alexisonfire announced they had been writing new music for their fifth studio album, describing it as "so heavy it's going to make Dog's Blood look like a ska record". However, on August 5, 2011, Alexisonfire announced their intent to break up. In the statement, George Pettit cited Dallas Green's departure from the band to focus solely on City and Colour, Wade MacNeil's departure to join another band, later revealed to be as the new vocalist for Gallows, and other personal issues among the remaining members as reasons for breaking up. Pettit also described the break up as not being "amicable". Alexisonfire had planned on celebrating their tenth anniversary with one last headlining Canadian tour and "a series of releases", although Green had initially expressed reluctance to take part in any further shows with the band at the time.  For Record Store Day 2012, Alexisonfire and Dine Alone re-issued Math Sheet Demos, which featured demo recordings of songs prepared in the pre-production of their self-titled debut album.  In July 2012, Green stated he had been in contact with other ex-Alexisonfire members, and that he and MacNeil had been "starting to talk about doing some final [Alexisonfire] shows, because when we did play our last show nobody knew it was our last show." In December 2012-15 months after the band's breakup announcement--Alexisonfire embarked on their international, farewell tour with stops in Canada, UK, Australia and Brazil, originally announced to be a nine-date tour. Due to demand, the tour was later extended to 15 dates. In December an EP entitled Death Letter was released, featuring new interpretations of songs spanning the band's previous four albums.

Answer this question "Why did Alexisonfire cancel their album" by extracting the answer from the text above.
Dallas Green informed the rest of the band of his intention to leave Alexisonfire in 2010. Green agreed not to announce his departure