このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語)：
rds cancel pending modification
対処
関連リンク
How do you remove/undo/delete a pending modification on Amazon ...
https://stackoverflow.com/questions/51679351/how-do-you-remove-undo-delete-a-pending-modification-on・・・
Error while modifying AWS RDS Parameter Group using AWS ...
https://stackoverflow.com/questions/31473946/error-while-modifying-aws-rds-parameter-group-using-aws・・・
AWS RDS: Can't get modify of Instance Class to go through ...
https://stackoverflow.com/questions/47021466/aws-rds-cant-get-modify-of-instance-class-to-go-through・・・
AWS, RDS. restoring instance from snapshot stucks in ...
https://stackoverflow.com/questions/43918571/aws-rds-restoring-instance-from-snapshot-stucks-in-pend・・・
AWS RDS parameter group showing "Pending-Reboot" after ...
https://stackoverflow.com/questions/41570431/aws-rds-parameter-group-showing-pending-reboot-after-my・・・
Amazon RDS DB インスタンスを変更する - Amazon Relational ...
https://docs.aws.amazon.com/ja_jp/AmazonRDS/latest/UserGuide/Overview.DBInstance.Modifying.html
Modifying an Amazon RDS DB Instance - Amazon Relational ...
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.DBInstance.Modifying.html
Amazon RDS Stuck in Modifying - AWS - Amazon.com
https://aws.amazon.com/premiumsupport/knowledge-center/rds-stuck-modifying/
RDS maintenance cancellation? : aws - Reddit
https://www.reddit.com/r/aws/comments/5bo740/rds_maintenance_cancellation/
Is it possible to cancel a planned maintenance for Amazon RDS? - Quora
https://www.quora.com/Is-it-possible-to-cancel-a-planned-maintenance-for-Amazon-RDS