Purpose

You have been given SendAs permissions to an account and you want to compose an email in Outlook for Windows

Solution

Step 1. Click 'New Email'

Step 2. Click the 'Options' tab

Step 3. Click 'From' in the ribbon

Step 4. Click 'From' in the Message section then choose 'Other Email Address...'

Step 5. Input the resource account Display Name or Email Address and click the 'Ok' button 

Step 6. You'll notice the resource account email address listed next to the 'From' listing