When in a catalog, collection or other list of titles, you can select an account to view at the bottom of your screen, in the Markup Bar:
Doing so will allow you to make account-specific suggestions, see their existing Edelweiss orders for the listed titles, and show you their sales and inventory data for comparable titles if they’re an Analytics store.
Note: If you do not see an account listed here, that means you’ve not yet added them to your Contacts. If you have added them, but still do not see them listed, you’ve likely added an email address that is different than the one they use to log in to Edelweiss. Your best bet is to verify with your account which email address they use. Some accounts may use a general email address for their store (email@example.com) rather than the personal email address you may be used to using (firstname.lastname@example.org).
Another possibility, if they are indeed listed in your Contacts, is that you might have “un-listed” them here:
More about adding your Contacts can be found here.