anchor.diff:  ==== Dry Run Modes
   
  -In some situations, it is necesary to preview what a given customer will be invoiced for at a given date or after making a subscription change.
  +In some situations, it is necessary to preview what a given customer will be invoiced for at a given date or after making a subscription change.
   Kill Bill provides dry-run invoices apis to accomplish such goal, and there are a few flavours for different use cases:
   
   * Next upcoming invoice: When is the next upcoming invoice for a given customer, and what will such invoice contain (items, amount, date, ...)?
   * Next upcoming invoice associated with a given subscription or bundle: When is the next upcoming invoice for a given subscription/bundle, and what will such invoice contain (items, amount, date, ...)?
   * Given a targetDate, what invoice will the system generate ?
  -* Subscription modification: Given a change in a subscription (new subscription, change of plan, cancellation,..), which invoice will the system generate ?
  +* Subscription modification: Given a change in a subscription (new subscription, change of plan, cancellation, ...), which invoice will the system generate ?
   
   
   
  
positive.code:  -H 'X-Killbill-ApiSecret: lazar' \
   -H 'X-Killbill-CreatedBy: demo' \
   -d '{"bundleId":"c056fac0-1564-46cd-9e2a-d97e49e30177", "dryRunType":"SUBSCRIPTION_ACTION",  "phaseType":"EVERGREEN", "productName":"Basic", "productCategory":"BASE", "billingPeriod":"MONTHLY", "priceListName":"DEFAULT", "subscriptionId":"06b826ad-73e6-4bdd-92fe-c9770a1ba30a", "billingPolicy":"IMMEDIATE", "dryRunAction":"CHANGE"}' \
   "http://127.0.0.1:8080/1.0/kb/invoices/dryRun?accountId=704b1a30-e5b9-4d01-b2b8-e9403a0ed0e3";
  ----
  
  The result is an invoice with 3 items:
  
negative.code: 
  ==== Subscription Modification
  
  Finally, we'll generate a dry-run invoice associated to a change in the subscription: We want to see what kind of invoice would be generated if we were to change the billing period from `ANNUAL` to `MONTHLY`. Also note that this changed was made on 2018-01-24:
  
  [source,bash]
  ----
  