Q: backup encryption

hi,

have a corporate iphone6 that cannot be backed-up by icloud.

the corporate policy requires an encrypted local backup.

i seem to have forgotten the password for the backup and want to create a new backup with a new password.

tried deleting the previous backup, re-installing itunes- it keeps remembering the previous password.

i would like to create a new encrypted backup with a new password.

i would appreciate if you could assist me in the process.