Managing Third Party credentials manually / API

Hi , 

Third Party Credentials questions.

1) Is it possible to update Third Party Credentials using API or any other option other than Manual. We are rotating our client Secret every 6 months so don't want to do it manually, exploring option to automate this process. 

2) Does Appian provide audit of updating Third party Credentials. e.g if we have S3 credentials and if someone updates client secret then does appian capture this update in any log  ?

Thanks

Vishal