Upgrading the AWS Lightsail instance

To upgrade your AWS Lightsail instance from the $44 plan to the $84 plan, you'll need to follow a process that involves creating a new instance from a snapshot of your current one. Here's the process and precautions to take:

1. Create a snapshot: Before upgrading, create a snapshot of your current Lightsail instance. This serves as a backup and will be used to create the new, larger instance.

2. Create a new instance: In the Lightsail console, go to the Snapshots tab and find the snapshot you just created. Click on the ellipsis (three dots) menu next to the snapshot and choose "Create new instance." During this process, you'll be able to select the larger $84 plan.

3. Configure the new instance: Give your new instance a name and select any additional options you need.

4. Launch the new instance: Create the new, larger instance based on your snapshot.

5. Update new instance's Firewall settings (if applicable): The new instance's Firewall settings will be reset to default new instance firewall rules. If you have made any edits to the Firewall settings of your original $44 instance, you will need to redo them on the new $84 instance. Please refer this doc for detailed steps.

6. Test the new instance: Before switching over, thoroughly test the new instance to ensure all your applications and services are functioning correctly.

7. Update DNS (if applicable): If you're using a domain name, you'll need to update your DNS settings to point to the new instance's IP address. If you're using a static IP, you can detach it from the old instance and attach it to the new one to maintain the same IP address.

8. Migrate data: If there have been any changes since creating the snapshot, ensure you migrate any new or updated data to the new instance.

Precautions:

1. Backup: Always create a snapshot before making any changes. This gives you a rollback option if needed.

2. Compatibility: Ensure your applications are compatible with the new instance type. While unlikely, some applications might be optimized for specific instance sizes.

3. Downtime planning: There may be a brief period of downtime during the switch. Plan this during a low-traffic period if possible.

4. Cost consideration: Be aware that you'll be billed for both instances until you stop or delete the old one. Make sure to remove the old instance once you've confirmed the new one is working correctly.

5. Performance monitoring: After the upgrade, monitor the new instance to ensure it's performing as expected and that you're effectively utilizing the additional resources.

Remember, you cannot directly upgrade an existing Lightsail instance. The process involves creating a new, larger instance from a snapshot of your current one. This method allows you to scale up while maintaining your data and configurations.
Sources
Upsize a Lightsail instance, storage, or database from snapshots - Amazon Lightsail
Move to larger Lightsail instance | AWS re:Post