You can’t change the home/away setting, your location will determine that.
You probably can set different away temperatures for different days. Easiest way would be with different flows.
When Home/Away status changes
AND
Koen’s phone is away
AND
It’s Monday
THEN
Change living room to 18 degrees
Generally it does not work anymore, the Homey Tado app does not support Geo location (Home/Away) anymore. Removed by Athom from the app, I think 2 weeks ago.
In the Dutch section we have spoken about some solutions:
App like MacroDroid (Geo + SSID detection) on an Android phone or Node-Red for reading the Tado status and send a webhook to Homey seems the most succesful.