Tests: Changing the Point Value of Test Questions After the Assessment Has Been Graded

Locate the Course Management menu
Locate Course Tools>Tests, Surveys, and Pools

Select Tests

Locate the test and select edit from the drop down menu next to the test name.

Locate the question(s) that need a point adjustment and check the box in front of the question.
(Select all is an option as well) 

Select Update and Regrade.