use this in a macro to cancel the Signed, Sealed job, it will not break your streak, it will just assign a new job.
/run iAbandonQuestID = 83055; C_QuestLog.SetSelectedQuest(iAbandonQuestID); C_QuestLog.SetAbandonQuest(); C_QuestLog.AbandonQuest();
EDIT: This no longer lets you continue the streak, looks like blizz changed it to just turn off jobs. So instead of fixing the problem, they removed the workaround.