One way:

Assume list is in column A. In column B:

B1: =IF(MOD(A1,10)=8,FLOOR(A1,10)+x,A1)

where x is the digit you want instead of 8.

Copy down. Copy column B. Paste Special/Values over column A. Delete
column B.

In article ,
Hammertime wrote:

If I have long list of three digit numbers in an Excel column that have the
number 8 in them how can I replace the 8 in the last digit (eg 458) without
changing the second digit when there is an 8 within it (eg 488). I've tried
"text to columns" & then concatenating but this disrupts the formular.
Thanks for any help you can provide.