Use 'in that case' to express clear outcomes of a situation, highlighting a consequence or action taken. She might not make it to the meeting. In that case, I'll present the report.
Pro Tip 2/3
Plan B Mention
Mention a backup plan using 'in that case' to show what alternative you will follow if the first plan fails. The café is full. In that case, let's grab a coffee from the kiosk.
Pro Tip 3/3
Implicit Understanding
'In that case' assumes the listener understands the situation or condition being referred to. You forgot your gym clothes? In that case, you can't join the class.