ISSUE:
Can the plaintiff have a cause of action under promissory estoppel?
Did the plaintiff waive his rights to a concession by accepting the action of partial exemption?
RULE:
Where the government makes a promise, even in sovereign, administrative or governmental capacity, knowing or intending that it would be acted on by the promisee and, in fact, promisee, acting in reliance on it, alters his position, the Government will be abstained to go back on its promise if it will be inequitable to do so, notwithstanding that there is no consideration for the promise and promise is in fact is not recorded in form of a formal contract as required by Article 299 of Constitution.