Customer price procedure by default in customer master data

Hi,

When I create a new customer, the field customer price proc KNVV-KALKS bring by default the value "1".

This value is set by account group.

For the account group Y001 : it's appear "1"

For the account group Y002 : it's appear "Z"

In wich transaction can we change this value by default in IMG.

Thanks

Omar