Mix in new salad dressing, say

• Mix anew, as a salad
• Flip again, as a coin
• Mix again, as a salad
• Throw again
• Mix over, as a salad whose walnuts have sunk to the bottom
• Liven up the greens, say
• Pitch again

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Retoss \Re*toss"\, v. t. To toss back or again.

Wiktionary Word definitions in Wiktionary
vb. To toss again; to throw back.