要更改Amazon FSx文件系统的委托管理员，可以使用AWS SDK for Python (Boto3)中的以下代码示例：

import boto3

Replace with the ID of the file system you want to modify.

FS_ID = 'fs-xyz123'

Replace with the ARN of the new delegated administrator.

NEW_ADMIN_ARN = 'arn:aws:iam::123456789012:user/john'

fsx = boto3.client('fsx')

response = fsx.associate_administrative_account( FileSystemId=FS_ID, AdministrativeAccountId=NEW_ADMIN_ARN, )

The response should contain the following key/value pair if successful:

{'Lifecycle': {'TransitionToIAMPending': True}}

注意：要使用此代码示例，需在代码中替换FS_ID和NEW_ADMIN_ARN变量。FS_ID应替换为要更改委派管理员的文件系统的ID。 NEW_ADMIN_ARN应替换为要委派为新管理员的AWS Identity and Access Management(IAM)用户或角色的ARN。