Αν αλλάξει το δρομολόγιο του τραμ, θα αργήσω πάλι στο γραφείο.

In Greek, after αν for a real future condition, you normally do not use θα.

So Greek says:

• Αν αλλάξει ... = If it changes ...

not

• Αν θα αλλάξει ...

A good pattern to remember is:

• Αν + verb
• main clause: θα + verb

So here:

• Αν αλλάξει το δρομολόγιο του τραμ, θα αργήσω...
• If the tram schedule/route changes, I’ll be late...

Αλλάξει is the form of αλλάζω used here after αν to talk about a possible future event.

Many learners will see it described as the aorist subjunctive or perfective non-past form.

Why this form?

Because the speaker means one specific change in the future, not a repeated or ongoing process.

Compare:

• αν αλλάξει = if it changes / if it ends up changing
• αλλάζει = it changes / it is changing / it usually changes

So αν αλλάξει sounds right for a future condition.

Because the sentence refers to a single possible future event.

• αν αλλάξει το δρομολόγιο = if the schedule/route changes
• αν αλλάζει το δρομολόγιο would not be the normal choice here

In this kind of future if clause, Greek usually prefers the perfective form, because the focus is on whether the change happens or not.

English does not show this contrast so clearly, but Greek does.

Δρομολόγιο can mean several related things, depending on context:

• route
• schedule
• service
• run/itinerary

With τραμ, it often refers to the tram’s route or schedule/service pattern.

So in this sentence, the exact English wording depends on the translation you were given, but grammatically το δρομολόγιο του τραμ means something like:

• the tram route
• the tram schedule

Του τραμ is the genitive and means of the tram.

What is interesting here is that τραμ is an indeclinable loanword for many speakers, so the noun itself often stays the same, while the article shows the case:

• το τραμ = the tram
• του τραμ = of the tram

So even though τραμ does not visibly change, the article tells you the grammatical role.

Because θα αργήσω refers to one future occasion: I’ll be late.

This is the normal choice when you mean a single event in the future.

• θα αργήσω = I’ll be late / I’ll arrive late
• θα αργώ = I’ll be late regularly / I’ll keep being late / I’ll take a long time

So in this sentence, the speaker means:

• if the tram route/schedule changes, this time again I’ll be late to work

That is why θα αργήσω fits better.

It can mean both, depending on context.

Common uses:

• Αργώ στο γραφείο = I’m late to the office / I arrive late at the office
• Αργώ να ετοιμαστώ = I take a long time to get ready

In your sentence, it clearly means to be late.

So θα αργήσω πάλι στο γραφείο means I’ll be late to the office again.

Here πάλι means again.

So:

• θα αργήσω πάλι = I’ll be late again

It usually goes near the word or phrase it affects, but Greek word order is fairly flexible.

For example:

• Θα αργήσω πάλι στο γραφείο
• Πάλι θα αργήσω στο γραφείο

Both are possible, though the emphasis changes slightly.

Στο is the contracted form of σε + το.

So:

• σε το γραφείο becomes στο γραφείο

This is completely normal in modern Greek.

Here στο γραφείο means to the office or at the office, depending on context. With αργήσω, the sense is basically be late to the office.

Yes. Greek word order is more flexible than English, because endings and articles carry a lot of grammatical information.

For example, these are both possible:

• Αν αλλάξει το δρομολόγιο του τραμ, θα αργήσω πάλι στο γραφείο.
• Θα αργήσω πάλι στο γραφείο, αν αλλάξει το δρομολόγιο του τραμ.

The basic meaning stays the same, but the emphasis can shift.

Be careful, though: moving πάλι can sometimes slightly change what sounds emphasized.

Because the sentence begins with a subordinate if-clause:

• Αν αλλάξει το δρομολόγιο του τραμ, ...

In Greek, when this dependent clause comes first, it is normally separated from the main clause with a comma.

So the structure is:

• If-clause, main clause

That is why the comma appears before θα αργήσω...