If I drop from my architecture studies in ETHZ Zurich, can I restart in Manchester?
The question can only be answered by an admissions committee at Manchester. But, like any other application, you need to show them that you are a good candidate to succeed in the program and afterwards. There is competition for any available slot and they want to make the best choices. 

A series of failures isn't a great endorsement. If you want to move, do so before the situation looks hopeless. 

However, there is an exception to the above. If you fail the exams for some odd reasons other than lack of preparation and diligence, then you might be able to have some professor speak highly enough of you that an admissions committee will make an exception. This is especially true if the professor has some personal or professional relationship with people on the receiving end. 

But an anonymous student with a poor record isn't likely to be an obvious choice for acceptance.