Você pode "voltar e fazer de novo" com um repeat
loop :
repeat
⋮
set response to …
if response is equal to "Help" then
Help()
else
exit repeat
end if
end repeat
Ou com repeat while
:
set response to "Help" -- just the inital condition
repeat while response is equal to "Help"
⋮
set response to …
if response is equal to "Help" then
Help()
else
end repeat