You can use XML-combine to override and extend an existing promotions template. If you do this, be careful not to break any promotions that have already been created based on the original template (if the promotion can no longer be displayed due to changes in the template, the user may be able to convert the template to use an Advanced Condition and Offer. Bear in mind that promotion assets cannot be deleted in Oracle ATG Web Commerce Merchandising.

Another option is to make changes in a copy of the original template, and then use the new version for future promotions.

Similarly, do not delete any templates unless you are certain that no promotions based on that template exist.