If there is an object in front of part of a person that you want removed, we have to guess what is behind the object and draw it in. If it is part of a sleeve or something basic that we can replicate, that isn't a problem; we can complete the request. However, if it is blocking part of your face or a large portion of your body, it isn't possible for us to realistically recreate it.
In some situations, we might be able to replace the blocking object with something nicer (i.e. covering a cell phone with a bouquet of flowers).