Hi,
It looks like you have users associated to two different registered locations of your company. We organize those locations ("parties") into a hierarchy reflective of the legal structure of your company. I see that you are the DA for the top "headquarters" party, while the individual you want to nominate as DA is currently associated to the lower-level party.
Assuming there is a reason why you want to keep your users grouped by location (instead of having everyone associated to the headquarters, which is the typical default, for simplicity purposes), you have two choices:
1.) If you want this new person to be an administrator only for users of the lower-level (subsidiary) location, then in Step 3 (Select Company), choose their current lower-level company location (instead of your headquarters location).
2.) If you want this new person to be an administrator for all users, at your top-level headquarters and all lower-level company locations, then you can use the "User-Company Associations > Change a User's Company Association" page to move them up to the headquarters location. Once that is done, you would be able to nominate them to be an additional DA for the headquarters and all lower-level locations.
If you don't have any need or desire to manage user access across multiple locations, then you can use the same above-referenced function to move all users to the headquarters location.
More information about managing access across multi-level company hierarchies is available via the "Help" link in the upper right corner of every CSAM page.
