How to update the user enrolment via the API

Hi,

We are using Moodle version 383 and we are trying to update the user enrolment date (start and end dates). We are trying to use core_enrol_submit_user_enrolment_form. If I looked in the documentation, it only says:

"Submit form data for enrolment form"  

It does not specify which fields to pass. We calling the function like this:

https://lms.rcmstg.com/lms/webservice/rest/server.php?moodlewsrestformat=json&wstoken=rcmtoken&wsfunction=core_enrol_submit_user_enrolment_form&formdata={"ue":"66422","ifilter":"0","status":"0","timestart":"1610480371","timestart":"1642092064"}

But it returns this error:

{"exception":"dml_missing_record_exception","errorcode":"invalidrecord",

"message":"Can't find data record in database table user_enrolments. (SELECT * FROM {user_enrolments} WHERE id IS NULL\n[array (\n)])",

"debuginfo":"SELECT * FROM {user_enrolments} WHERE id IS NULL\n[array (\n)]"}

The "ue" value is correct. What are we doing wrong?