Urgent clearing cooling off period

Dear Student room,

I am an IB student who already has my results, I have started going through the clearing process and have two offers I am unsure of which expire on the 7th and 8th of august respectively,…. Ideally I would like to ask city university or soas for spots on their courses through clearing, problem is all lines are closed until a level results day and by then my offers will have expired. one of the universities which has given me an offer stipulates a 14 day “cooling off” period after accepting them as my clearing choice on UCAS, does this mean UCAS let’s me substitute this clearing choice for another one if it is within this timeframe after I have accepted? This might let me talk to the universities I want to go to more without jeopardising me going to uni come september.