Dwija varnas i.e. Brahmins, Kshatriyas and Vaishyas use specific sutras(known as GrhyaSutras from specific vedas for doing sandhyakarma, and shraddhakarma etc for e.g. A rigvedi brahmin who belongs to ashvalyana sutra/shakha uses it to do his daily sandhyavandana.
I want to know weather one can change the sutra associated with his family and gotra, because there are many cases where the system is long forgotten due to effects of time.
There might be a possibility of changing or reassigning the shakha by a rishi but there are no more rishi's so it is not an option.
I also want to ask if anyone can become Chatur-vedi by studying all vedas but maintaning his own veda shakha.