"Restart Call" feature

[burris]

I wonder how they could do this if one of the connections is PSTN.

Maybe on a VOIPo to VOIPo call, but haven't you ever gotten a bad connection on a land line to cell or cell to cell or land line to land line?
Just how much trouble is it to redial?
Are we that lazy.

[mikeb]

Sounds like it would be best to address the root cause of the problem. A phone service where some calls are fine and others are poor is not acceptable. Submit a ticket and see if the poor quality calls can be fixed.