Hello. I want to change a bunch of formulas in a column but it's very complicated.

Here is an example. I want to change

=SUM('ACTUALS summary'!AL115:AO115)*1000
to
=SUM(INDIRECT("'ACTUALS summary'!AL115:"&O8&"115"))*1000
by using a find and replace.

BUT even if I can figure out how to do a find and replace for that, it gets complicated because while the other formulas have the same pattern, they are slightly different.

For example, I also want to change
=SUM('ACTUALS summary'!AL116:AO116)*1000
to
=SUM(INDIRECT("'ACTUALS summary'!AL116:"&O8&"116"))*1000