I need to change the order (degree) of the elements I am using in a mesh How do I do this using ABAQUS?

In the Mesh module click on the Element Type icon. In the dialog box which appears choose the element order you require (from the available list : Linear, Quadratic) 
If using the quadratic (2D) and Hex elements (3D) choose Incompatible Modeelements if using the lower order elements.