Global Change to Formulas in Conditional Formatting

Hi there. I have been looking for a solution to this problem for a while with no luck. I am hoping someone can tell me IF what I am looking to do can be accomplished or not.

I have a spreadsheet where I have used conditional formatting to create a bar chart on a calendar to show progress of a construction schedule. The formula looks to data on another sheet and changes the color of the progress bar (='HIDDEN SHEET'!$I$13="S1" and SI would turn the cell blue, S2 turns it green, etc., for a total of 5 conditions per cell) Now I want to make a global change to the thousands of cells changing the reference sheet in the formula from "HIDDEN SHEET" to "HIDDEN SHEET_2" (leaving the cell references along) without going into each cell and editing the formula.

Does anyone have any ideas if this can be done in a global "find/ replace" way?

Thank you.

yes.

I am trying to attach a pdf of the spreadsheet but it is taking too long