Please give us some greater detail.  Pictures help as well.  See the Snip & Sketch if you are not sure how.

It's hard to tell you how to fix if we cant see what you did.

Hi Robert. Yeah, I agree with Scott. You didn't give us enough information to work with. Let's see some pics of your database.

Tables - PayItem (Lists all pay items with descriptions, unit cost, etc. relationship is PayItemID (primary key) - parent
            ChangeOrder (lists ChangeOrderID (primary Key), ChangeOrderNo, PayItemNo  relationship is PayItemID - orphan

Form created to query by ChangeOrderNo Combo Box is querying based on ChangeOrderID which is primary key.  Want to force query to query by ChangeOrderNo.  When entering new items to specific Change Orders, a unique ChangeOrderID is being assigning an item to the change order.  Multiple items may be listed on a Change Order so multiple ChangeOrderID's are assigned to the Change Order No. hence duplicate Change Order No are displayed on the drop down list.  Is there any way to force a query solely on Change Order No.  I did use the Select Distinct statement in the SQL.  Still no luck.

I'll get pics if still not clear.  Note:  When I pull up the records based on the Change Order No, all the pay items are displaying properly in my form.  

Yeah, your field/table names are meaningless to me. I need to see it in action. See Context.