ACR - Accounts - I want to update the ACR linked in the Accounts, how can I do it?

You have to do 2 different things:

1/ Create a new version of the ACR under the Audit tab and update it as needed in SFC2014, then send it again to the Commission.

2/ Create a new version of the Assurance package in the Accounts module in SFC2014. Update the link of the ACR with  the new version and send it to the Commission.