To manually override a citation you have already created, position the cursor on the citation you want to manually override and click to select it.
In the edit panel of Mendeley Cite, you can now see your selected citation with the manual override option box above the reference pills. To enter the manual override mode, select the 'manually override the citation' link.
Within the manual override panel you will see a text box containing the original citation default text. You can now change the values by typing in the text box and editing the default text. You also have the option to suppress the author name. Once you have finished editing the citation text, select 'Save changes' to apply these changes to your document. If you wish to cancel any changes you have made, just select 'Close'.
To undo any manual changes after you have saved them, reselect the citation to open the manual override panel. Select the 'Revert to default' button to revert the citation back to its original value. Select 'Save changes' to finish editing your citation.