Take another's place and keep one begging (9)
I believe the answer is:
suppliant
'one begging' is the definition.
(I've seen this before)
'take another's place and keep' is the wordplay.
I cannot really understand how this works, but
'place' could be 'pl' (I've seen this in other clues) and 'pl' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for suppliant that I've seen before include "One making an appeal" , "Beggar" , "One begging" , "Asking earnestly" , "One who begs humbly" .)