Si quieres cambiar la cita, dímelo antes.

If you want to change the appointment, tell me beforehand.

Breakdown of Si quieres cambiar la cita, dímelo antes.

• querer: to want
• tú: you
• me: me
• cambiar: to change

Questions & Answers about Si quieres cambiar la cita, dímelo antes.

Why is it si quieres and not some other form of querer?

Because quieres is the tú form of querer in the present tense: tú quieres = you want.

So si quieres... means if you want...

This sentence is speaking to one person informally. If you were speaking more formally in Spain, you would say:

• Si quiere cambiar la cita, dígamelo antes. = if you want to change the appointment, tell me beforehand.

Why is it si quieres cambiar and not si quieres que cambie or a subjunctive form?

Because after querer followed by another action done by the same person, Spanish normally uses the infinitive.

So:

• quieres cambiar = you want to change

The structure is:

• querer + infinitive

Examples:

• Quiero comer = I want to eat
• ¿Quieres venir? = Do you want to come?

You would use que + subjunctive when the second verb has a different subject:

• Quiero que vengas = I want you to come

But in si quieres cambiar la cita, the person who wants and the person who changes are the same person, so cambiar is correct.

What exactly does mean here?