Programm that converts a character capitalization

I'm making a programm that, if the user inputs a lowercase character, the programm generates it's character in uppercase, and the opposite too. I'm using a function in order convert the character into lowercase or uppercase based on ASCII table. Lowercase to uppercase is being converted correctly, but uppercase to lowercase is not. I dunno if I'm messing it up:

char changeCapitalization(char n)
{
    //uppercase to lowercase
    if(n>=65 && n<=90)
        n=n+32;
    //lowercase to uppercase
    if(n>= 97 && n<=122)
        n=n-32;
    return n;
}