To change a tag’s value:
Enter the following command and parameters:
euca-create-tags [resource] --tag [key=value]
Eucalyptus returns a the resource identifier and its tag key and value. The following example changes the value of the stack tag for one of your EMIs from prod to test:
euca-create-tags emi-1a2b3c4d --tag stack=dev
TAG emi-1a2b3c4d image stack dev