BE 2014 logon account not editable

Dear All,

I check my backup job was failed because account issue, when i lookup to BE 2014 logon account it is not editable. They all are greyed out except for the server. This is normal? how can i edit my logon account for different database?

Here i include the picture.

Image may be NSFW.
Clik here to view.

Best regards,

Iqbal