Recover root password of DP4440

Hi all,

I have one DP4440 unit, the previous employer has changed the default password and he left the company without any handover, i need to setup this kit so is there anyway we can recover/reset the root password of system manager or do we need to factory reset the unit ? i can get into iDrac but couldnt find any option for system manager. any help would be appreciated.

Thanks