Trying to create a conditional with a username

[Realen]

hi guys ~

i need help trying to code a name question but im trying to repeat the "enter your name" if the user just press enter without type nothing

print('Welcome')

user_name = (input('Please enter your name:'))

if user_name  == input(''):
    print(f'Hi {user_name}! im here to help you')
else: 
    print('Please enter a name')

thanks for the help