If good–faith negotiations between Alberta and Canada are unsuccessful following Alberta’s successful referendum on independence, Alberta can still appeal to paragraphs 154 and 155 of the Quebec Secession Reference for guidance.1 Specifically, para 155 says that following unsuccessful negotiations, a province may issue a de facto declaration of independence and pursue international recognition of sovereignty.
Therefore, if talks between Ottawa and Alberta collapse despite Alberta’s democratic mandate, Alberta can maintain its mandate by issuing a de facto declaration of independence dependent on recognition from the international community.
1The Quebec Secession Ruling is available here: https://decisions.scc-csc.ca/scc-csc/scc-csc/en/item/1643/index.do