Learn Turkish: Otel rezervasyonu yarın bitecek. - The hotel reservation will end tomorrow.

The verb root is bit- (to end). Since it ends in a consonant (t), we do not need the buffer letter y. Then, we follow e-type vowel harmony. The vowel in bit- is i, which is a front vowel, so it takes the -ecek ending to become bitecek.

Why doesn't bitecek have a personal suffix at the very end?

The subject of the sentence is otel rezervasyonu (the hotel reservation), which corresponds to the third-person singular pronoun o (it). In Turkish, the third-person singular does not take an extra personal suffix in the future tense.

Why is there a -u at the end of rezervasyonu?

This is a noun compound. In Turkish, when you put two nouns together to make a new concept like "hotel reservation", the second noun gets a possessive suffix. Because rezervasyon ends in a consonant and its last vowel is o, 4-way vowel harmony gives it the suffix -u.

Is bitmek the standard verb to use for a reservation ending?

Yes! Bitmek means "to end", "to finish", or "to run out". It is the most common and natural verb to use for a time period passing, an event wrapping up, or a reservation expiring.