Possible to change Node Email address?

Is it possible to change the SNO email address without destroying the identity?

Yes, you can easily change the address, just like any other parameter in the docker run command.

If you want to change any of your parameters, such as payout address, allotted storage space, bandwidth, etc., just stop the container: docker stop -t 300 storagenode
then remove the container: docker rm storagenode
and then run the container again, after editing the parameter that has changed, in your case
-e EMAIL="user@example.com"