Hi @Jack Nairn ,
Thanks for your reply!
Based on my research, i found that when the shared mailbox is automatically mapped to the Outlook client or added as an additional mailbox, the "Rename" option is grayed out. To make the "Rename" option available, we need to remove automapping for a shared mailbox in Outlook and add the shared mailbox to your outlook client as an separate account. Please refer to the following steps:
1.File>Info>Add account.
2.Enter Name and shared mailbox address>click Next.
3.A very critical step: in the pop-up window for entering the password, do not enter the password, and click "sign in with other account" below.
4.Log in as an account with shared mailbox permission.
5.Shared mailbox configuration succeeded and remember to restart Outlook.
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