question concerning multiple addresses

[tech_related]

Hello everyone,

I retrieve email from two different email accounts, and I would like to be
able to *send* email from both addresses; after looking at the manual I
thought that perhaps "$alternates" was the right variable, but, according to
the manual, it only defines which addresses mutt recognizes as "mine" when
it comes to saying whether email is "From:" me or "To:" me.

How can I send email from two different addresses?

Thank you for any tip,

Manuel