Call on (5)
I believe the answer is:
visit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">call on</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for visit that I've seen before include "Look up" , "Pay social call" , "Come to see" , "Go and see (someone)" , "Call on (someone)" .)