Customers are assigned to a sales rep by assigning the appropriate rep number to the customer on the customer record.
You can see and edit the sales rep assignments for your customers in one or both of the following ways. The Edit Customers section in webmanager will allow you to view/edit the sales rep assignments for your customers which are listed under the Rep Number header.
You can also view/edit your customer list in bulk on an excel spreadsheet which can be exported from the Manage Data > Export Data section of Web Manager.
ALL Sales Reps should have a unique rep #. No two reps should have the same rep #. If you have two reps with a parent/sub-rep setup, they should still both have unique rep #s but then you can assign the sub-rep to the parent rep within the setup.