In order to access or modify your credentials in Credential Manager via a Process, open Process Designer and proceed as below:
1) Via the "Get Credential" action, the credentials table can be retrieved.
2) Via the "Set Variable" action, you can set a new value to a credential, while specifying it by its name. For instance, you could use the following structure - %PRCredential["Password"]% = MyNewPassword. Make sure that the credential's attribute is typed within double quotes.
3) Finally, use the "Update Credential" action, in order to update the corresponding Credential.