Impact of force Changing of password - DDIC, SAP* etc.

Hi,

Could you please let me know the impact if we force change the password.

Impact with respect to

Dialog users like --> DDIC, SAP* etc.

Other types of users like --> System, Communication, Service

Basically I would like to know what things should be taken care,

if we change the password of the above users.

Thanks & Best Regards

Raghunahth L