As the heading says I want to close a Sales Return Order form via the API but I have very little information on how to achieve that.
This is the first time for me working with a sales return order in BC and what I have read is that I can be quite tricky since there is no documentation.
Q: Do I need to develop an action with AL to achieve that?
At the moment there is no standard API in Business Central for Sales Return Orders.
This means the answer to your question is: Yes, you must extend Business Central with the requested functionality through AL.
Have a look at how the ShipAndInvoice
procedure is implemented in the Sales Orders API. It is basically the same you want to do for Sales Return Orders.
Take a look at this question here on StackOverflow regarding how to call the bound action on the API.