Here's an example of how to do this in SageMath 9.5 operating under Jupyter Notebook:

var_names_orig = ['x_1', 'x_2'] pol_ring_orig = PolynomialRing(QQbar, names=var_names_orig, order='degrevlex')

var_names_reord = ['x_2', 'x_1'] pol_ring_reord = pol_ring_orig.change_ring(names=var_names_reord, order='lex')

pol_orig = 2 * all_vars_orig[1] + 3 * all_vars_orig[0]^2

pol_reord = pol_ring_reord(pol_orig)