Authorisation Notifications Frequency and Embed Link to Authorise

Afternoon Everyone,

Two parts to this question:

1) Is there a place or is it possible to change the frequency of POP Authorisation Notifications?
I have a problem where PO Notifications are not being sent in some cases, or not at all.
or
if say a user creates a PO Requisition and the option "Authorise and Generate Order" is used,
then that PO that has been created also requiers Authoristaion it does not send any notifications

Yet if I gview or amend the PO and manually add a new notification it sends that almost straight away and then also sends the previous one that did not send ???

2) Is there a way to amend the URL that is embeded in the Email for a user to click the link to to back to the PO?
I just need to amend the ServerName

Thanks,
Paul