One route you can go is to create the new item the second list and set the Case ID when the new item is created. You should be able to get the list item ID for the item and store it in a workflow variable. Then use that variable to update that item via with the Update Item action with the Date and Amount information. You could also use the Case ID in the Update Item action to match the new list item.

Thanks for your input.

The second is used solely for the purposes of getting the repeating section information out from the first list. I can't create item in the second list.

I figured out how to query list to get the case ID I need from the first list, but I can't get the Update item part works. 

@CherieWong I assume that your Case ID is outside the repeating section.

• You can connect that Case ID control to a SharePoint column.



• You also connect your repeating section to plain text multiline text column in SharePoint



• Now in workflow:
  
  
  
  
  
  • Using Query XML and multiline text column you get date and amount in the collection
  
  
  
  • Using For loop, Index and collection operations:
    
    
    
    
    
    • Get each date and each amount
    
    
    
    • Using Create Item action you create an item in your List 2
      
      
      
      
      
      • List 2 Case ID column --> Use the Current Item, field value of Case ID
      
      
      
      • List 2 Date ---> use the workflow variable --> dt_eachDate
      
      
      
      • List 2 Amount --> use the workflow variable --> slt_eachAmount
      
      
      
      
      
      
    
    
    
    • I suggest you put commit pending changes action after Create Item action
    
    
    
    
    
    
  
  
  
  
  
  

Now if you have 4 rows in repeating section then it will create 4 items in your list 2.