Abdicate

Abdicate [ab-di-keyt] 

Verb 

- to renounce or relinquish a throne, right, power or claim, esp. in a formal manner
- fail to fulfill or undertake (a responsibility or action)

Synonyms:

renounce, relinquish, resign, abnegate, cede

Usage:

1. The king was forced to abdicate.
2. The government was accused of abdicating it's responsibility.

Antonyms:

seize, take over, assume, secure