First, you will need to visit your Admin Menu, in the top right, the four squares icon pictured below.

Then, under Employment, you will click on the Staff Departments and Sections / Job Roles button.

You will then see a list of your company's job roles, to edit one of the job roles click on the edit button on the left hand side.

Here you will now be able to Edit the Job Role, and select the department that the role belongs to.

Click Save to finalise your changes.