Using RENAMEVARS without assigning to a workspace variable does not modify the table's variable names. Use t = renamevars(t,vars,newnames). The number of new variable names must match the number of variables specified. A table variable subscript must be a numeric array containing real positive integers, a logical array, a character vector, a string array, a cell array of character vectors, or a vartype subscripter object. Renaming dimension names is not supported using RENAMEVARS. New variable names must be text. Specify 'NewVariableNames' as Constant.