I sometimes need to delegate access to a single-user/shared user website for short term administration purposes (eg. with a junior administrator for programmed maintenance).
I have requested multiple accounts, but apparently it is not an option.
My solution would be to change the password to a shared value before access, and change it back to the default password after.
I would record both passwords in the company password manager.
Do you see problems with this approach, and do you have a better suggestion?