The most common and most likely answer to this crossword clue is the 6 letter word ENCORE
I've seen this crossword clue in The Daily Telegraph
E
N
C
O
R
E
More clues leading to the result ENCORE
- Call for more RE once, strangely
- Space centre’s to give work once more
- English name, actor, regularly referring to repeat performance
- Evidently north leads with heart again!
- Conclusion somewhat lacking heart again!
- Once more performing without little Maureen? Yes
- Corporal maybe about to undermine base again!
- Repeat prescription once more, not involving the doctor
- I want more from officer before coming round
- Last cut – heart, again!
Buddy explains!

The straight part
We know that "Call for more" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case call for more = encore.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ENCORE mean?
ENCORE noun- A brief extra performance, done after the main performance is complete.
- A call or demand (as by continued applause) for a repeat performance.
- To call for an extra performance or repetition of, or by.
- To call for an encore.
- To perform an encore.
- (said by audience members after a performance) Please perform again!