Two solutions come to mind:
:2,6norm eeanot<CR>
We use :norm[al]
to execute the normal mode command eeanot
on lines 2 to 6.
:2,6s/can/¬<CR>
We run a classic substitution on lines 2 to 6. In the replacement part, &
represents the matched text so we don't have to repeat can
before not
.