How to create a shared resource using the curl api

hi! I have administrator credentials for nextcloud and can generate a curl post request to create a shared access for the administrator user.
The question is, how to generate a curl post request to create a shared resource from a frodo user whose password is unknown to me, but the nextcloud administrator password is known?

NC 25.0.3
PHP 8.1
mysql version 15.1 Distribution 10.6.11-MariaDB