Verb conjugation of "convalidar" in Spanish

I ordered a cab at four o'clock in the morning which took me to the Central Bus Station. I was much to early because the bus would go just at seven o'clock. Anyway I was sitting there and listening to music.
I tried to explain that I was preferring to eat with everybody together I that I preferred not to eat meat if they did not eat it either, for financial reasons. I thought that they understood my feelings.
That was a funny coincidence and she told me about some good parties on the island. I went to one these parties which was actually located in an open air bar. There were few people but everyone connected.