You have just opened a big can of worms. Your issue is an issue that many companies struggle with and as per usual there is no straight answer to your question.
The first thing you need to consider is whether you really need the ESU.
Secondly, you will need to determine if the ESU is part of a large ESU, fixing many issues and addressing many SARs over a multitude of objects.
If the ESU is relatively small and only affects one or a couple of objects, a possible strategy is to apply the ESU to a separate environment (eg Pristine). Be absolutely sure about the objects that are affected!
If in your case the only affected object is the UBE itself, you can proceed.
After the application create a new project and move the UBE to this project and check it out. You can now use the new ER Visual compare tool which will allow you to copy Event rules from Pristine to your object (presumably in DEV).
This still will not guarantee you have copied the complete ESU as this method will only review ER and will not look at the design of the UBE, but if you're lucky this method will work
Unfortunately the only 100% method is to apply the ESU as per the normal procedure and re-apply the modifications.
Are there any other tips out there?
Sef van den Nieuwelaar
B732 on NT, XE on NT, B732/A73 on AS400, B733 on NT