From June 2019, you can customise the form Toolbar to include a tool to Bulk update the status of the forms related to it.
Configure the Toolbar
1. Go to Configure then Document types
2. Select the Document type you want to configure this option for
3. Tick the Bulk Update Status for Linked docs button. (You can customize the name of the button if required)
4. 
5. This adds the option to the Toolbar as shown below
6. 
...
Bulk Update Status of Linked Forms
1. To Bulk update the status of items Go to the required form
2. Click on the ... Button, then Bulk Update Status for Linked Docs
3. 
4. You will be shown a list of the Form types linked
5. 
6. Select the form type you would like to Bulk update
7. It will then list the forms with their current status
8. Select the status you would like to change the forms to and click Update
9. 