From what I can tell you are adding an element into Endevor and you want Endevor to modify the lines of code of the element? If that is the case, I do not believe it will do that. But you can do that within a processor and write it out to a different library. I have a similar case where we have JCL/PROC/SYSIN types that we migrate through Endevor but we want to validate those at each stage of the lifecycle. A File-aid/file manager utility is used within my processor, when those types are added into Endevor it is a skeleton with symbolic values that the File manager will replace and write to a different output library. That way we can validate at each stage, it also has a step that will remove the concatenation of libraries as the JCL moves forward.
In Development - - JCL will have concatenation of DEVL/QUAL/PROD
IN QUAL - DEVL is dropped as we don't want to look back, 1st library concatenation is QUAL then PROD
IN PROD the only library is EMER and then PROD staged libraries.
I hope this is what you were looking for, if not sorry that I took up your time.
Phon