[asterisk-users] strip + sign from incoming ${EXTEN} var?

[voiplist]

Is it possible to strip the plus sign from the ${EXTEN} var on an incoming call?

We have our system setup to deal with incoming calls to numbers
without a plus sign, lots of AGIs and databases we don't want to have
to change.

We have seen things like this ${EXTEN:1} which you can use in the dial
command but we want to basically change the ${EXTEN} var right off
when it comes into extensions.conf before we do anything else.

I have read that since this is a built in Asterisk variable and it can
only be read, not written to.

We know there are other ways to handle this but we were just hoping
for a simple solution like resetting the variable.

Any help would be appreciated.