Do they all originate from the same footprint?
If yes, you only have to do it once for one footprint.
- open one of them in the fp editor
- change one pad how you want it
- r-click on it and select ‘export pad settings’
- r-click on another one and select ‘import pad settings’
- after you got all changed, save the footprint
- close the fp editor or just go back to pcbnew
Now we change all of them in one swoop (make a backup of the project kicad_pcb file now, just in case)
- r-click on the edited footprint
- select ‘edit parameters’
- click ‘change footprint’ button
- select options accordingly, probably the 2nd or 3rd from top for your case
- hit ‘apply’ button
I hope it works, as otherwise you have to replace them, one by one.
Procedure is same as above.. get to ‘change footprint’ window for each of the ones that need changing and instead of being able to swap them at once, click on ‘list footprints’, select the one you have modified and click ‘apply’. Repeat as necessary.
Good luck