You could try:

/castsequence [target=party1] reset=11 Renew,Null

This will cast renew on the first click (at Party 1).
Subsequent clicks will not do anything, as we are on the Null.
However, it won't reset to Renew until 11 seconds of not pushing the macro at all has occurred.
This means, if you push it every 10 seconds, it will never reset.

If this is on a key you spam, then I'd suggest adding commas for timing.
Even if its not exact always, as long as it is close, that will probably work.
Just tweak the commas, adding or removing them until you have something close.

If this is not a spammed key, you could try putting it on the same keybind as the DK has Death Strike.
Then only hit the key when the DK's spell is ready.