The antonym for "re-serving" can be "discard" or "throw away." When we re-serve something, it means we are presenting it again for consumption or use. However, if we discard something, we are getting rid of it entirely without any intention of using or consuming it in the future. It is the opposite action of re-serving. Instead of reusing or presenting, we are dismissing and getting rid of it. Another possible antonym for re-serving can be "reject," "refuse," or "decline." These words mean to turn down or refuse the offer of something, whereas re-serving means to accept and take it.