To edit an existing Check-in in Slack, navigate to Troopr home tab where you can see the list of all your Check-ins. Choose the Check-in, Click on "Other actions" ⇒ "Edit"
Click on "My Check-ins" to list all of your Check-ins. In the Check-in you want to edit, choose "Other actions" ⇒ "Edit" to launch the Check-in editing form.
The form is the same as the one for creating the Check-in and allows you to change any of the Check-in attributes.
Upon submitting the changes, you will get an acknowledgement message similar to the creation acknowledgement. No messages will be sent to participants about the changes.