There is an extreme need to enable a proxy access for HR specialists, Line Managers to be able to act on behalf of employees to troubleshoot issues in performance module and other modules.
See an oracle cloud customer connect idea lab:
https://cloudcustomerconnect.oracle.com/posts/99b949f99b?page=2

Indeed this function has been presented in early versions of Fusion HCM, then has been replaced by a new delegation feature that provides ability to delegate some roles and approval functions for a certain period.

But It turned out that Impersonation and Proxy Users feature is supported by the Sales module.
See: https://docs.oracle.com/en/cloud/saas/engagement/19b/oscus/user-management.html#OSCUS2041467

In this article I would like to explain a trick that allows you to setup a proxy feature for HCM pages based on the sales impersonation privilege.

The main issue is that a “Switch To” feature is not accessible from HCM stripe, so you need provide an access to any page for CRM/FSCM stripes.
Fortunately a seeded Employee role provides an access to Tools->Reports and Analytics page, so we can accommodate it.
In case you use a custom roles you need add privileges that grant access to Tools->Reports and Analytics page.

To configure a proxy feature I followed steps below:

• Create a custom job role with a role category: CRM – Job Roles. Alternatively you can add an “Impersonate User” privilege to existing custom HR specialist role.

• Add a Impersonate User privilege in the Function Security Policies train-stop

• Assign it to users that will act as a proxies. You can do it later in Security Console
• Login as a regular employee and setup a proxy user access to his UI pages and data

• Login as a proxy user and go to the Tools->Reports and Analytics page and you will be able to see “Switch To” feature

I hope this workaround will be helpful.

Kind regards,
Volodymyr