The call will terminate once everyone has hung up.
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	2:det	_
2	call	call	NOUN	NN	Number=Sing	4	nsubj	4:nsubj	_
3	will	will	AUX	MD	VerbForm=Fin	4	aux	4:aux	_
4	terminate	terminate	VERB	VB	VerbForm=Inf	0	root	0:root	_
5	once	once	SCONJ	IN	_	8	mark	8:mark	_
6	everyone	everyone	PRON	NN	Number=Sing|PronType=Tot	8	nsubj	8:nsubj	_
7	has	have	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	8	aux	8:aux	_
8	hung	hang	VERB	VBN	Tense=Past|VerbForm=Part	4	advcl	4:advcl:once	_
9	up	up	ADP	RP	_	8	compound:prt	8:compound:prt	SpaceAfter=No
10	.	.	PUNCT	.	_	4	punct	4:punct	_
