de-escalate
1. [ verb ] diminish in size, scope, or intensity
Examples:

"The war of words between them de-escalated with time"

Related terms: decrease de-escalation
2. [ verb ] reduce the level or intensity or size or scope of
Synonyms: weaken step_down
Examples:

"de-escalate a crisis"

Related terms: escalate decrease decrease
Similar spelling:   de-escalation
  decalitre
  decaliter