PBA-S has the following Billable Resources in Virtual Machine Hosting Plan (VM HP):
Top > Billing Director > Product Manager > Hosting Plans > VM HP > Billable Resources --->8--- Number of domains with DNS hosting provided. Number of Static IP addresses. Number of Static IPv6 addresses. ---8<---
Only these resources may be upgraded in a Virtual Machine through PBA-S. See provider's guide for the detail.
Here is the scheme:
Create destination Hosting Plan in PBA-S with the same Virtual Machine Template Name:
Top > Billing Director > Product Manager > Hosting Plans > VM HP > Template Name
Increase Billable Resources in the destination Hosting Plan as you like.
Change Hosting Plan of the subscription through CP usual way, with the "Change Hosting Plan" button.