Keystore change passwords

Changing keystore password

$ keytool -storepasswd -keystore keystorename
Enter keystore password:  <old password>
New keystore password: <new password>
Re-enter new keystore password: <new password>

Changing keystore alias password

$keytool -keypasswd -keystore keystorename -alias aliasname
Enter keystore password:  
New key password for <aliasname>: 
Re-enter new key password for <aliasname>:

Note:

**Keystorename**: name of your keystore(with path if you are indifferent folder) 
**aliasname**: alias name you used when creating (if name has space you can use \) 
for example: $keytool -keypasswd -keystore keystorename -alias stop\ watch

[How can I] Change the password, so I can share it with others and let them sign

Using keytool:

keytool -storepasswd -keystore /path/to/keystore
Enter keystore password:  changeit
New keystore password:  new-password
Re-enter new keystore password:  new-password

Keystore only has one password. You can change it using keytool:

keytool -storepasswd -keystore my.keystore

To change the key's password:

keytool -keypasswd  -alias <key_name> -keystore my.keystore

To change the password for a key myalias inside of the keystore mykeyfile:

keytool -keystore mykeyfile -keypasswd -alias myalias