Let me see if I understand you correctly.
You want to change:
You have to do that for 30 columns. So in the next column you will need to change:
And so on...
If you remove the quotation marks, excel will automatically alter the column reference when dragged across columns.
And drag this formula to the right for the A2 to change into B2, C2 etc...
I just noticed that =INDIRECT("'Sheet1'!A2") with quotation marks does exaclty the same as ='Sheet1'!A2 !
I was going to suggest to maybe use find&replace but now I'm lost as to why change the formula when the result is going to be the same???