The sales order approval process involves a two-step confirmation, requiring initial approval followed by a final acceptance or rejection by a web admin. Once fully approved, customers can access the sales order to accept or reject it.
Here is a reference video:
Goto Manage Rental menu
Click on Sales Order option
Open a sales order with status created, by clicking on action icon to edit
Scroll down, click on Approve button
Once approved it will ask for 2nd level approval. There will be an Accept & Reject button. Click Accept to confirm from web admin level.
Note: After approval customers will have access to the sales order so that they can accept or reject.