How to retain deltas when you change LO extractor in Production system

Sometimes we come across scenarios wherein LO cockpit extractor is delivering daily deltas from SAP R/3 to BW system and there is a requirement to add new fields to this extractor.Since this change is to be done in R/3 Production system,there is always a risk that daily deltas of LO cockpit extractor would get disturbed. If that happens then we have to do re-initialization which is costly in terms of time & resources. I am providing a step-by-step procedure to minimize the risk of delta queue getting broken /disturbed.