Upgrade from SQL express to SQL standard

I have taken a snapshot of the express sql db and there are no options to restore to a standard sql db contrary to a similar question answered here - https://aws.amazon.com/blogs/database/modify-an-amazon-rds-for-sql-server-instance-from-standard-edition-to-enterprise-edition/ https://repost.aws/knowledge-center/rds-sql-server-change-engine-edition Please assist with next steps to perform this upgrade