I think it would be something like:

=IF(ISERROR(VLOOKUP($A5,Reroute!$A$2:$V$362,7,FALS E)),
$A5,VLOOKUP(Reroute!$A$2:$V$362,7,FALSE))

That depends on if the original address is in A5. Also, I don't know
the purpose of
having the absolute column reference in $A5.

Dan