find and replace for indirect

Hello. I have these formulas (there are 100+ but all of the same pattern) down a column.

=SUM('ACTUALS detail'!AM72:AQ72)
=SUM('ACTUALS detail'!AM73:AQ73)
=SUM('ACTUALS detail'!AM87:AQ87)
=SUM('ACTUALS detail'!AM92:AQ92,'ACTUALS detail'!AM93:AQ93)

How can I do find and replaces to make the formulas like this:
=SUM(Indirect("'ACTUALS detail'!AM72:"&AT&"72")
and for the ones with multiple selections
=SUM(Indirect("'ACTUALS detail'!AM92:"&AT&"92,'ACTUALS detail'!AM93:"&AT&"93")

I don't want have to do that manually for each cell. Thanks.

I need to change it to indirect because the values were hardcoded and I don't want to have to do a search and replace every time I want to change the values. AT in this case is a value of a column that changes automatically so if I indirect it, the cell formulas will reference that. Make sense?

Somebody else recommends this but I get the following error after I try the first find and replace "the formula you tried has an error"...and it won't complete the replace.

It looks like three times will do it...

Find:
SUM(
Replace with:
SUM(INDIRECT("

Find:
:AQ
Replace with:
:"&AT&"

Find:
)
Replace with:
")

@ FDibbins. You're a mofuggin genius THanks.