cooperate

verb5

1. •
   to join with other people and help each other so that all of them reach the same goal
2. •
   To allow for mutual unobstructed action.
3. •
   To function in harmony, side by side.
4. •
   To engage in economic cooperation.
5. •
   To obtain the cooperation of (a potential witness); to turn (someone) into a cooperating witness.