Learn@UW/D2L  Editing Existing Equations
You can make changes to existing equations that were created with the Equation Editor within the HTML Editor:
To do so:

Within the HTML Editor Leftclick on the existing equation.

Click the 'Graphical equation' icon ( ), 'MathML equation' icon (<>), or 'LaTeX equation' icon ( \ ) that appears in the toolbar, depending on how the equation was inserted.

This brings up an 'Edit Equation' interface matching the Insert Equation interface used when the equation was inserted (Graphical Editor, MathML, or LaTeX).

Make any desired changes to the equation.

Press Insert to return to the HTML Editor.