Either can Invite
When you connect with a member, both of you will see an "Invite to Checkin" button at the top of your chat.
Propose a time to Checkin
Tap "Invite to Checkin" to propose a day and time to Checkin.
Accept or Decline
Once sent, the invitee will be notified and can to Accept or Decline the invitation from the Chat. If you need to cancel the invite, Tap "Uninvite" at the top of your chat.
If the invitee accepts the proposed time, the Checkin is scheduled. If they decline, the "Invite to Checkin button will re-enable and either member can propose a new time.