Prayer: Abandoning the Intention for a Ten-Day Stay
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1327
If a traveller intends to stay somewhere for ten days, in the event that before he performs a four rakʿah prayer within its prescribed time he abandons the idea of staying there, or he becomes unsure of whether to stay there or go to another place, then in such a case, he must perform qaṣr prayers. However, if after performing a four rakʿah prayer within its prescribed time he abandons the idea of staying there or becomes unsure, he must perform tamām prayers as long as he stays there.