you biggest issue is not so much revenue, but billing, actually. The old sales order will not be able to create a remaining monthly billing schedule š. So it will have to be reverting the existing SO/Billing/Rev to the point of now (or May) and re-generating SO with the new monthly billing schedule and same revenue. On rev side - when you create CM (or Return Authorization) it will have its own rev plan, and original rev plan will still continue to run so essentially you will have three rev plans for your sale at the end of the day