Η αλλαγή στο πρόγραμμα είναι προσωρινή.

Η is the definite article meaning the.

Here it matches αλλαγή (change), which is a feminine singular noun, so the article also has to be feminine singular:

• η αλλαγή = the change

Greek articles change for gender, number, and case, unlike English the, which always stays the same.

In Greek, every noun has a grammatical gender: masculine, feminine, or neuter.
Αλλαγή is simply a feminine noun.

A lot of nouns ending in -ή are feminine, so that ending gives you a useful clue:

• η αλλαγή
• η ζωή
• η φωνή

But gender is something you still need to learn with each noun, ideally together with the article.

The dictionary form is αλλαγή. It means change.

In this sentence it is in the nominative singular, because it is the subject of the sentence:

• Η αλλαγή ... είναι προσωρινή.
• The change ... is temporary.

Because στο is the normal contraction of:

• σε + το = στο

So:

• στο πρόγραμμα = in the program / on the schedule / to the program, depending on context

This contraction is extremely common in Greek:

• σε + την = στην
• σε + τον = στον
• σε + το = στο

So learners should think of στο as a very standard form, not as slang or an optional shortcut.

It tells you where the change is: in the schedule/program.

Greek often uses σε for ideas that English may translate as:

• in
• on
• at
• to

So στο πρόγραμμα is a natural Greek way to say something like:

• in the schedule
• in the program
• to the program

The exact English preposition depends on the context, but the Greek structure is completely normal.

Here πρόγραμμα is after στο (σε + το), so it is in the accusative.

But πρόγραμμα is a neuter singular noun, and for many neuter nouns the nominative and accusative forms are identical. So it looks unchanged:

• nominative: το πρόγραμμα
• accusative: το πρόγραμμα

That is why you do not see a different ending here.

Είναι means is and is the 3rd person singular of είμαι (to be).

So the sentence structure is:

• Η αλλαγή = subject
• στο πρόγραμμα = extra information
• είναι = is
• προσωρινή = predicate adjective

Greek normally uses είναι in this kind of sentence, just as English uses is:

• Η αλλαγή είναι προσωρινή.
• The change is temporary.

Because adjectives in Greek must agree with the noun they describe.

The noun is:

• η αλλαγή = feminine singular

So the adjective must also be feminine singular:

• masculine: προσωρινός
• feminine: προσωρινή
• neuter: προσωρινό

That is why the sentence says:

• Η αλλαγή ... είναι προσωρινή.

Because προσωρινή is being used as a predicate adjective, not as an adjective directly attached before a noun.

Compare:

• Η αλλαγή είναι προσωρινή. = The change is temporary.
• Η προσωρινή αλλαγή = the temporary change

In the first sentence, προσωρινή comes after είναι and describes the subject, so it does not need its own article.

Yes. Greek word order is more flexible than English word order.

The neutral, straightforward order here is:

• Η αλλαγή στο πρόγραμμα είναι προσωρινή.

But Greek can change the order for emphasis, for example:

• Προσωρινή είναι η αλλαγή στο πρόγραμμα.
• Στο πρόγραμμα η αλλαγή είναι προσωρινή.

These alternatives may sound more marked or emphasize a different part of the sentence, but the basic meaning stays the same.

Not always. It depends on context.

πρόγραμμα can mean things like:

• program
• schedule
• timetable
• plan

So in this sentence, στο πρόγραμμα may be understood as:

• in the schedule
• in the program

If the English translation you were shown uses schedule, that is perfectly natural.

The accent marks show which syllable is stressed:

• Η αλλαγή → stress on the last syllable: al-la-YI
• πρόγραμμα → stress on the first syllable: PRO-gram-ma
• είναι → stress on the first syllable: EE-ne
• προσωρινή → stress on the last syllable: pro-so-ri-NI

Greek stress is important, because it is part of the correct form of the word.

That would sound unnatural in ordinary Greek.

The most natural place for προσωρινή is after είναι, because it is the main description of η αλλαγή:

• Η αλλαγή στο πρόγραμμα είναι προσωρινή.

Greek word order is flexible, but not random. Some orders are natural, while others sound awkward or overly marked.

It is a very common Greek pattern:

definite article + noun + prepositional phrase + είναι + adjective

Here:

• Η αλλαγή = the subject
• στο πρόγραμμα = prepositional phrase
• είναι = verb to be
• προσωρινή = adjective describing the subject

So it is a useful model for many similar sentences, such as:

• Η λύση στο πρόβλημα είναι απλή.
• Η κατάσταση στο σχολείο είναι δύσκολη.

This makes the sentence a good example of both article-noun agreement and adjective agreement in Greek.