Hi, I am new in genieacs. I tried to change the password of Wifi using genieacs. However, the password is shown to be changed in Genieacs GUI but it does not change in the CPE. 
For example here I tried to update passphrase as testwifi@123 in CPE, but even after I updated it - it is the same as it was before.
GenieACS will only send changes to the CPE. For passphrases, the way to work around this is refresh the value and then set it to the desired value. The reason this works for passwords/passphrases is the spec specifically says that all passwords will be returned by the device as empty string.
If this still does not work, then you will need to turn on debugging and post the soap conversation between the CPE and ACS.