Joletec, Inc

Connect to your Office 365 instance.

$UserCredential = Get-Credential
Connect-MsolService -Credential $UserCredential

Show your license SKUs

 

Get-MsolAccountSku

 

Run the command to change your user's licenses All At Once (example is from Office 365 Education for students to  Office 365 Education Plus for student )

get-MSOLUser -All | where {$_.isLicensed -eq "TRUE" -and $_.Licenses.AccountSKUID -eq "[School]:STANDARDWOFFPACK_STUDENT"} | Set-MsolUserLicense -RemoveLicense "[School]:STANDARDWOFFPACK_STUDENT" -AddLicense "[School]:STANDARDWOFFPACK_IW_STUDENT"

 

10 At a time (Test it)

get-MSOLUser -All | where {$_.isLicensed -eq "TRUE" -and $_.Licenses.AccountSKUID -eq "[School]:STANDARDWOFFPACK_STUDENT"} | select -Last 10 | Set-MsolUserLicense -RemoveLicense "[school]:STANDARDWOFFPACK_STUDENT" -AddLicense "[School]:STANDARDWOFFPACK_IW_STUDENT" 

 

Note: It takes a long time to finish.  I ran it on about 2800 students and it took around 45 minutes to complete.