To change the password of a pfx file we can use openssl.
Open a command prompt.
Navigate to the openssl folder:
Extract the private key with the following command:
openssl pkcs12 -in C:\Temp\SelfSigned1.pfx -out C:\Temp\SelfSigned2.pem -nodes
(You need to enter the old password, when requested!)
Then create a new pfx with the new password:
openssl pkcs12 -export -out C:\Temp\SelfSigned2.pfx -in C:\Temp\SelfSigned2.pem
Now, you’ll be asked for the new password.
The resulting pfx file can be used with the new password.
Hope it helps!