Can I remove knee braces in garage?
Those were almost certainly added for a reason since even in 1955 builders did not add extra components to a structure needlessly.
You will need a building permit and in order to get that you'll need plans.  For those plans you'll need an engineer's stamp since you are changing the structure in a major way.
My recommendation is to hire a licensed engineer who can examine your current structure and give you some options to accomplish what you want.