Is it possible to transfer a reserved instance from one availability zone to another?

Transferring a reserved instance from one availability zone to another is indeed possible, and this flexibility is one of the advantages of AWS’s reserved instances. When you purchase a reserved instance, you're essentially securing a specific instance type for a one- or three-year term in a specific region, which includes multiple availability zones.

However, while the original purchase of a reserved instance is tied to a specific availability zone, you can modify the allocation of the instance to apply to other availability zones within the same region. This allows customers to make adjustments based on their operational needs, such as changing workloads or scaling requirements.

This option provides significant value, especially in environments where workloads change and it's necessary to optimize resource allocation. It allows businesses to adapt to evolving demands without incurring extra costs associated with on-demand instances, thus providing both flexibility and cost efficiency.

In contrast, the other potential answers would imply constraints that don’t apply. For example, it is not limited to the instance's operational status, nor is there a restriction based on the age of the instance. This flexibility is a key feature of the reserved instance model in AWS.