Exchange 2010 one email address is associated with two mailboxes

I have a user who was mistakenly setup in AD and Exchange by his Middle name (which he goes by) but company policy requires us to set him up my his legal first name. Instead of just changing the existing account another admin created a new one and just moved over the other email address as an alias to the new account. Now in exchange that email address is associated with two mailboxes/AD accounts. We are a large company with several sub email domain names.

Username1 should have these email addresses:
Username1@internalDomain.com
Username1@PrimaryDomain.com

Username2 should have these email addresses:
Username1@AliasA.com (His Middle name that he wants as his Primary SMTP address)
Username2@AliasA.com
Username2@internalDomain.com
Username2@PrimaryDomain.com


When I open Exchange Management Shell and run
[PS] C:\windows\system32>get-recipient -Identity Username1 -resultsize unlimited | select Name -expand emailaddresses | Select SmtpAddress

SmtpAddress
-----------
Username1@internalDomain.com
Username1@PrimaryDomain.com



[PS] C:\windows\system32>get-recipient -Identity Username2 -resultsize unlimited | select Name -expand emailaddresses | Select SmtpAddress

SmtpAddress
-----------
Username1@AliasA.com (His Middle name that he wants as his Primary SMTP address)
Username2@AliasA.com
Username2@internalDomain.com
Username2@PrimaryDomain.com


[PS] C:\windows\system32>get-recipient -Identity Username1@AliasA.com -resultsize unlimited | select Name -expand emailaddresses | Select SmtpAddress

SmtpAddress
-----------
Username1@AliasA.com (His Middle name that he wants as his Primary SMTP address)
Username2@AliasA.com
Username2@internalDomain.com
Username2@PrimaryDomain.com

[PS] C:\windows\system32>Get-Recipient -Identity Username1@AliasA.com

Name                                                        RecipientType
----                                                             -------------
Username2                                               UserMailbox
Username1                                               UserMailbox



My question is how do I get this email address associated with only Username2?
JCGITAsked:
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JCGITAuthor Commented:
Closing question: I figured it out. Username1 had a UPN of Username1@AliasA.com and Username2 had a SMTP of Username1@AliasA.com I changed the UPN and now it shows:

[PS] C:\windows\system32>Get-Recipient -Identity Username1@AliasA.com

Name                                                        RecipientType
----                                                             -------------
Username2                                               UserMailbox
0

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