Can I select which email address I use to respond in Lollipop? I have multiple email addresses. I have one through my ISP, work, gmail etc. 

My problem is that I'd like to be able to choose which address I use to respond to an email. For example, if my boss sends something to my gmail, I'd like to respond using my work email without copying and pasting the whole thing. 

In previous versions of Android, there were different apps for different types of email accounts but in 5.0 the gmail app handles all email. Is there a way to choose the from address when responding?
Not a Lollipop specific solution, more in general- works in other versions.


First you need to access your GMail account through your desktop browser. 
Click the Settings cog in the upper right and choose "Settings".
CLick on the "Accounts and Import" tab/section.
Find the option labelled "Send mail as: (Use Gmail to send from your other email addresses)". Should be the third one down. Click "Add another address you own".
Follow the prompts in the popup to add your other email account (address, username, password, server, etc.).
Once finished, GMail will send a verification email to the account you're trying to add. Open up that secondary email account, open the verification email and either click the URL to verify or enter the verification code. 


Now open up your GMail app on your phone (may need to reload it first). Try to reply to a message. If  you look at the "From:" line, there should now be a dropdown arrow at the right. Tap on it (or the email address) and there's be a dropdown where you can choose your newly added account.