assign one record at a time in a multiuser form

[neeko1226]

I'm trying to avoid record locking in a multiuser Access form. My thought is to assign one record in the table to the analyst by populating a field with their ID when they open the form. When they move to the next record, the form will close and then re-open looking for the next available record with where ID field is null (not being reviewed by another user). Here's the code I'm trying to get to work:
DoCmd.RunSQL
"SELECT TOP 1 tblQueue.QARep " _
& " FROM tblQueue" _
& " WHERE (((tblQueue.QARep) Is Null)" _
& " SET tblQueue.QARep = [Forms]![frmLogin]![txtLogin]"