Here is how you can adjust assignment due dates and availability dates in bulk or individually in Canvas.
Navigate to Assignments in the left menu.
On the Assignments page, select the vertical ellipses then Edit Assignment Dates.
View Assignment Dates
All graded items will appear, including assignments, discussions, and quizzes, along with their Title, Due At date, and Available From/Until dates.
You can edit assignment due dates in bulk by selecting them manually or selecting all assignments that fall within a date range. Enter a date range and then select Apply.
To edit dates in bulk, click Batch Edit. Here you can Shift Dates forward by a certain number of days or you can Remove Dates for all selected assignments.
You can also change individual assignment dates.
Save Updated Dates
Canvas will display a success message once dates have been saved.