Not in service and Simmer down

Simmer down and not in service are semantically related. In some cases you can use "Simmer down" instead an adverb phrase "Not in service".

Simmer down verb - Become quiet or calm, especially after a state of agitation.

Not in service and simmer down are semantically related. Sometimes you can use "Not in service" instead an adverb "Simmer down".