I have a seven day global pass which is valid for month. Once I activate this pass and I'm staying in a city for more than a day. So can I stop the ticket for those days and activate it again before I start travelling? I'm so confused with this.
No, once you have activated the pass it will remain active during the whole validity period of the pass. You can't deactivate a pass after the start date.
What is important is that you wait with activating your pass until just before boarding the first train of your travel. And that you do the same when connecting journeys to your pass. Only connect the journey to the pass just before boarding the train.