I have projects that I manage and projects that other people manage where I fullfill a role.
So it is important to communicate and to discuss urgencys and eventual deadlines.
A similar structured reply would be.
Dear Projectlead,
I am unavailable to perform that task at the moment.
Thanks.
Regards,
normal
And even if it is my DirectX superior, there is no need to involve thanks.
Just write:
Hi normal,
I need you to do X until Y/immediatly.
Greetings,
Projektmanager
When this is done you can thank me for performing the task, but otherwise it just feels like a structure telling me:
End of discussion!
I am able and willing to follow orders without this.