Why does a System Administrator need to modify an existing User/Contact?

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How to add Authorized Representative role to an existing system user?

If Users with only Authorized Representative role cannot be invited through Manage Users/Contacts. For more details, please click here.

However, if the user is an existing system user, the Authorized Representative role can be added to their profile as given shown below:

Click the user name link to make changes to the selected user's information.

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