The Date collection is read-only by design. It is not possible to change the bar's date (see
FAQ). You could try to set up a new custom Bars object etc. (see QuickRef > SaveToFile etc.) but before anything else, have you reviewed the already existing PnF strategies such as...
1. Built-in "Point and Figure Basic (PnF)"
2. Downloadable
ActiveTrader 2011-02 | PnF Double Top