Help with data Hook to replace time fields with a specific time.

Apologies for the delay. Once again thank you very much for taking the time to post such a detailed response. You efforts are hugely appreciated.

I have manage to get this to work but I only needed to use and slighly modify the code below. As I already had the code for formatting the times. My only issue remaining is this only works for new data and won’t update my existing times. Is there a ways to force it to update?

            **if**  ( item . nights  <=  5 ) { 
            //4PM - 4PM 
            item . startDate  =  **new**  Date ( sYear ,  sMonth ,  sDay ,  16 )  //4 PM 
            console . log ( item . startDate ,  'start' ) 
            item . finishDate  =  **new**  Date ( eYear ,  eMonth ,  eDay ,  16 )  //4 PM 
            console . log ( item . finishDate ,  'start' ) 
        } 

        **if**  ( item . nights  >=  6 ) { 
            //12PM - 12 PM 
            item . startDate  =  **new**  Date ( sYear ,  sMonth ,  sDay ,  12 )  //12 PM 
            console . log ( item . startDate ,  'start' ) 
            item . finishDate  =  **new**  Date ( eYear ,  eMonth ,  eDay ,  12 )  //12 PM 
            console . log ( item . finishDate ,  'start' ) 
        } 



            **return**  item  

}