The quick answer
Keep the standing Customer conditions under Criteria. Add Sales Rep under Available Filters and show it in the result filter region. A viewer can then select a rep for a narrower result set and clear the selection to return to the base search.
The screenshots use fictional Customer and Sales Rep data. Counts in this walkthrough illustrate the filter behavior, not a promised result in another account.
Before you start
Open a Customer saved search you can edit, or make a working copy. Confirm that the intended viewers can see the search and the Sales Rep field. Decide which conditions always apply and which choices viewers should be able to change in the results.
01. Set the base criteria
In Criteria > Standard, the example limits State/Province to CA or WA. These conditions define the base population. The Sales Rep selection will further narrow those rows; it does not replace the saved criteria.
02. Show the useful columns
Under Results > Columns, include identifying Customer fields and Sales Rep. Seeing the assigned rep beside each row makes the filter's effect easier to verify. The example also displays state so the base CA or WA condition remains visible.
03. Add the available filter
Open Available Filters and add Sales Rep. In the example, both Show in Filter Region and Show as Multi-Select are selected. Save and run the search. Available Filters makes a viewer control; entering a specific Sales Rep in Criteria would instead fix that rep in the saved definition.
04. Select a Sales Rep
In the result filter region, choose Avery Chen in this walkthrough. The example narrows to two rows assigned to that rep. Read the visible Sales Rep column and the result count together; a changed count by itself is weaker evidence than matching row values.
05. Clear and verify
Clear the Sales Rep choice. The example returns to five base rows. Check that the CA or WA criterion remains in effect and that the rep selection no longer limits the results. If viewers see a different control or fewer options, confirm their role, permissions, and field visibility in the actual account.
Common questions
Why put Sales Rep under Available Filters instead of Criteria? Available Filters gives a viewer a choice on the results page. Criteria defines the standing search population.
Does clearing Sales Rep remove the state rule? No. The CA or WA criterion remains part of the saved definition in this example.
Why does another viewer see different reps or rows? Role permissions, field visibility, and account data can affect what they see. Verify the search with the viewer's role before relying on it.