Once believed to be a rather tight option, Amazon Web Services Reserved Instances (RIs) can now be modified to get the most out of them. Amazon’s latest announcement indicates that EC2 users can migrate their Reserved Instances (RIs) between availability zones in the same region and between Network Platforms.

Reserved instances are basically the same as on-demand counterparts, but are a lot less pricey as compared to hourly computer charges when users commit to long term usages – typically a year or three years. Before yesterday’s announcement users had to commit to a certain reserved instance size and availability zone (AZ) – both of which are not changeable.

“We are excited to announce the ability to migrate your Amazon EC2 Reserved Instances (RIs) between Availability Zones in the same Region and between Network Platforms (to and from Amazon VPC),” Amazon notes in the announcement.

With the latest modification users can request a migration of the RIs between different Availability Zones as well as between EC2-Classic and EC2-VPC network platforms – if users’ account supports them. The update will prove to be a worthwhile for those users who face heavy loads on their instances at times and are required to buy more compute if they don’t have a reserved instance in that particular Availability Zone.

Reserved Instance calculations could be troublesome at times and there are quite a few companies that provide planners or RI calculators for AWS – a simple Google search would list a handful.