Working memory (WM) flexibly updates information to adapt to the dynamic environment. Here, we used alpha-band activity in the EEG to reconstruct the content of dynamic WM updates and compared this representational format to static WM content. An inverted encoding model using alpha activity precisely tracked both the initially encoded position and the updated position following an auditory cue signaling mental updating. The timing of the update, as tracked in the EEG, correlated with reaction times and saccade latency. Finally, cross-training analyses revealed a robust generalization of alpha-band reconstruction of WM contents before and after updating. These findings demonstrate that alpha activity tracks the dynamic updates to spatial WM and that the format of this activity is preserved across the encoded and updated representations. Thus, our results highlight a new approach for measuring updates to WM and show common representational formats during dynamic mental updating and static storage.