[RTC or EWM] I want to make and update APPROVALS using "REST API"
2 answers
No, there is no public supported REST or otherwise public supported HTTP based API available to create, update Approval data in EWM work items. There is a reportable REST API that allows to GET the data - look at the example on my blog.
The only public supported API's that support create and update Approval data in EWM work items are the EWM SDK and the Plain Java Client Libraries.
I am getting alarmed about all the questions you ask about APIs and wonder what you intent to do with all these APIs. The questions I start asking myself are around, what the purpose of all this would be, why you need to do it, who pays for it, is it worth it? Why APIs?