verb
reciprocate
rih-SIP-ruh-kayt/rɪˈsɪprəkeɪt/
To return an action or feeling with a similar one.
When neighbors help us, we try to reciprocate their kindness.

Etymology
Latin reciprocare describes movement back and forth. Reciprocate applies that returning motion to social responses: an action or feeling is answered with a similar one.
In context
you need to reciprocate you need to respond positively to offers of cooperation but also respond negatively it is to some degree to defections
More examples
- He loves her, but she does not reciprocate his feelings.
- I smile at the cashier, and she reciprocates.
- They invited us to dinner, so we reciprocated the following weekend.
Forms
reciprocate · reciprocates · reciprocated · reciprocating
reciprocation noun — Returning an action or feeling in kind.
reciprocal adjective — Given or felt by both sides toward each other.