Hi there!
You basically need to get the details from the “pending folder” entry as JSON and post a configuration change accordingly. It depends on whether the folder is already added on the “receiver” as you call it, and the inviting device just needs to be added to the list of shared device IDs, or you need to set up the shared folder at all with a new path to sync?
The jq command line tool will be helpful to transform the JSON data. This previous topic may be of interest:
Hope that helps. Let me know if you get stuck.