https://www.epo.org/en/service-support/faq/myepo-services/myepo/managing-user-access-myepo/patent-attorney-i-work-patent

As a patent attorney, I work in a patent law firm A, but I have my own private practice B. I would like to have access to the files of A and to my own files of B. Can I do this?

Yes, you can access both portfolios under which ever company you are entered as a recipient.  You can only be entered once as a recipient, for which we use your representative number. This number allows access to your complete portfolio, and can only be used for firm A or firm B.

If you have a colleague in firm A, who is also a professional representative, you can form an association. You could manage all your applications for firm A under the association number, and add that as a recipient for firm A.  Then all communications and portfolios for Firm A would be available there.

For firm B you can manage all applications under your own name, add yourself as a recipient with your own representative number and have all the communications and portfolio available under firm B.

If you are not in a position to form an association with a colleague, you will have to decide between using firm A or firm B to access communications and portfolios in MyEPO.