Have a party, say (9)
I believe the answer is:
celebrate
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">have a party say</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for celebrate that I've seen before include "Honour; make famous" , "Commemorate or eulogise" , "Put out the flags" , "Have a party to mark a happy event" , "Have festivity for special day or occasion" .)