How to modify a global variable in python and how to add a list to an array that is returned by a function

Question

I'm currently having issues with a program I'm making. It has four functions: Decodes the string (obligatory to use it as string) into an array:

list = 'Ana;Mora;Tencio°3-3456-0987°F ^Juan;Arias;Quirós°1-0654-1345°M ^Enrique;Miranda;Ortega°5-6547-8745°M ^' \'María;Montero;Fonseca°1-6654-7458°F ^Angela;Montero;Fonseca°2-6654-7458°F'

def decodeList():
    person = list.split('^')
    sepNCG = [sep.split('°') for sep in person]
    names= [sepX[0] for sepX in sepNCG]
    name = [i.split(';',1)[0] for i in names]
    firstLn= [i.split(';',2)[1] for i in names]
    secondLn = [i.split(';',3)[2] for i in names]
    code= [code[1] for code in sepNCG]
    gender = [gen[2] for gen in sepNCG]
    n = 0
    array= []
    while n != len(person):
        person = [[name[n],firstLn[n],secondLn[n]],code[n],gender[n]]
        n += 1
        array.append(person)
    return array

Now the second one should add a new person to the string (the parameters come from an input function):

def add(name,firstLn,secondLn,code,gender):
    global list
    if gender == True:
        gender= 'M'
    elif gender == False:
        gender = 'F'
    person = '^'+name+';'+firstLn+';'+secondLn+'°'+code+'°'+gender+'^'
    list = list + person
    return list

Now, this returns the string with the new data, but if I were to run the decode function again (using a menu so the program isn't stopped) the new data isn't there.

Now for the third one:

def removePerson(code):
    global lista
    for i in lista:
        if code in i:
            lista.remove(i)
            return lista
        elif cedula not in lista:
            return 'Person not in list'

With this one happens the same, so my question is how do I do change it so that add and removePerson change the string so that when I run the decodeList function it does it with the changes previously made?