To actively resume or restart an activity by the subject.
When to use
Subject acts directly, Active resumption, Resuming meetings or tasks
The nuance
Used when the subject actively resumes an action; it is an active verb.
재개하다 (jae-gae-ha-da, jaegaehada) · 재개되다 (jae-gae-doe-da, jaegaedoeda)
'재개하다' is used when the subject actively resumes an action, while '재개되다' is used for passive situations where the action is resumed due to external factors.

One lane per word — no nested boxes, just the gist.
To actively resume or restart an activity by the subject.
When to use
Subject acts directly, Active resumption, Resuming meetings or tasks
The nuance
Used when the subject actively resumes an action; it is an active verb.
To be resumed or restarted due to external factors or circumstances (passive).
When to use
Resumed by external factors, Passive situation, Resumption of interrupted work
The nuance
Used when the subject undergoes the action passively, resumed due to external factors; it is a passive verb.
회의를 재개하다.
hoe-ui-reul jae-gae-ha-da., hoe ui reul jae gae ha da.
Appropriate for an active situation where the subject resumes the meeting.
회의가 재개되다.
hoe-ui-ga jae-gae-doe-da., hoe ui ga jae gae doe da.
Correct for a passive situation where the meeting resumes due to external factors.
우리는 프로젝트를 재개되다.
u-ri-neun peu-ro-jek-teu-reul jae-gae-doe-da., u ri neun peu ro jek teu reul jae gae doe da.
‘재개되다’ is passive and cannot be used with an active subject like ‘we’; use ‘재개하다’ instead.
프로젝트가 재개하다.
peu-ro-jek-teu-ga jae-gae-ha-da., peu ro jek teu ga jae gae ha da.
‘Project’ is not an agent, so active ‘재개하다’ is incorrect; use passive ‘재개되다’.
수업을 재개하다.
su-eop-eul jae-gae-ha-da., su eop eul jae gae ha da.
Appropriate active expression when the subject directly resumes the class.
수업이 재개되다.
su-eop-i jae-gae-doe-da., su eop i jae gae doe da.
Correct for passive meaning where the class is resumed due to external circumstances.
그는 회의를 재개되었다.
geu-neun hoe-ui-reul jae-gae-doe-eoss-da., geu neun hoe ui reul jae gae doe eoss da.
‘He’ is an active subject and should use ‘재개하다’; ‘재개되었다’ is incorrect here.
회의가 재개하였다.
hoe-ui-ga jae-gae-ha-yeoss-da., hoe ui ga jae gae ha yeoss da.
‘Meeting’ is not an agent, so active ‘재개하다’ is inappropriate; use ‘재개되다’.
Which sentence is correct?
Which expression means ‘The project was resumed’ correctly?
Which phrase fits ‘We resumed the work’ best?