[pgh1969pa]

Updating a PRL (Preferred Roaming List) is going to have zero impact upon a sound quality issue between phones / BT headsets. Also, I can understand the hesitance of Sprint Techs to jump into this with both hands because this largely sounds like a compatibility issue with one or a couple of components (phones, headsets). They possibly can not test every combination of phone and headset with other phone and headset combination. You need to do some basic troubleshooting yourself to narrow down the cause before talking to a tech. With amount of information given, I would give you a bunch of different answers too. Do you have any more information regarding the frequency the issue and more particulars of the problem?

Does the echo on the Pre happen indoors & out? Does it happen with just one BT headset or all BT headsets? Is she always in the same room when it happens? In the car? Did you swap BT headsets to see if the problem follows? Try different BT headsets? Do any of these BT headsets have noise cancellation?

I've had echo issues with some BT headphones indoors that went away outdoors. The potential causes are many and the details provided are few.

What have you tried so far?