Can we create/update Approval field in work item type through Rest APIs?
One answer
As far as I can tell, 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. An example is shown in https://rsjazz.wordpress.com/2012/10/01/adding-approvals-to-work-items-using-the-plain-java-client-libraries/ .