How to change the value of the email tag to point to a different URL?
You can do this without any coding. Open the email template(s) and replace the <CONTENTREF> tag with the following hard-coded URL that will dynamically resolve the Domain ID and Issue Number. Of course, if you want the email notification to be for the CR, you will need to change that last part to PHI_CR_NUM=<CRNUM>. After making the change, you can easily test the effects by using the ad-hoc email feature directly in the Issue or the CR. Click on the ad-hock email button in the upper right corner. This feature will show you exactly what the email text will look like with all the tags resovled.
https://yoursite.com/psp/phire/EMPLOYEE/PT_LOCAL/c/PHI_MENU.PHI_ISSUE.GBL?Page=PHI_ISSUE&Action=U&PHI_DOMAIN_ID=<DOMAIN>&PHI_ISSUE_NUM=<ISNUM>