Unable to update Transaction Comments on an Asset using Standard REST API

Summary:

I am using Standard REST API : https://*****:****/fscmRestApi/resources/11.13.18.05/erpintegrations to update TH_ATTRIBUTE2 in FA_MASS_ADDITIONS table for a specific mass addition id, however nothing is getting updated.  Can you please help us with right parameter to pass in API request to update "TH_ATTRIBUTE2" field.

Sample JSON Request :

{

"OperationName": "processTransaction-updateMassAddition",

"ParameterList": "{P_MASS_ADDITION_ID : 12345, P_CAT_TH_ATTRIBUTE2 : Test Transaction Header"

}