wǒ xiǎng yánqī huànzhèng.

In this sentence, 想 means want to, would like to, or am thinking of.

So 我想延期换证 means something like:

• I want to postpone renewing my document/license
• I’d like to delay the renewal

Compared with 要, 想 usually sounds a little softer and less forceful.

Mandarin does not need an infinitive marker like English to.

In English, you say:

• I want to renew it later

In Mandarin, the pattern is simply:

• 我 + 想 + verb phrase

So:

• 我想延期换证

literally follows:

• I + want + postpone renewal

This is completely normal in Chinese.

延期 means to postpone, to delay, or to extend the time limit.

It is often used in fairly formal situations, especially for:

• applications
• deadlines
• permits
• official procedures
• renewals

So here, 延期 means that the speaker wants the renewal/replacement of the document to happen later than originally planned.

换证 literally means change/replace the certificate/document.

In real usage, it often refers to renewing or replacing an official document such as a:

• driver’s license
• permit
• ID-type document
• professional certificate

So even though 换 literally means change or replace, in administrative contexts 换证 can often be understood as renew a license/document.

It is best understood as one combined idea:

• to postpone the document-renewal process
• to delay renewing/replacing the document

So 延期 is affecting the action 换证.

It does not mean:

• first postpone something,
• then separately do another unrelated action.

Instead, the whole phrase is about delaying the renewal/replacement.

Chinese often leaves out information that is already clear from context.

So 换证 by itself can work if both speaker and listener already know what document they are talking about.

For example, in a government office or a conversation about a driver’s license, you might not need to say it again.

If you want to be more specific, you can add the document:

• 我想延期换驾照。 — I want to postpone renewing my driver’s license.
• 我想延期换居留证。 — I want to postpone renewing my residence permit.

Yes, you could, but the feeling is slightly different.

• 我想延期换证 = I want to / I’d like to postpone the renewal
• 我要延期换证 = I am going to postpone the renewal / I want to postpone it with a stronger, firmer tone

In many situations:

• 想 sounds softer and more polite
• 要 can sound more definite, direct, or determined

If you are making a request or discussing options, 想 is often the safer choice.

Yes, it is natural, especially in an official or administrative context.

It sounds somewhat formal because words like 延期 and 换证 are common in bureaucratic language.

In everyday speech, people might also say things in more expanded ways, such as:

• 我想把换证时间往后推。 — I want to push the renewal time back.
• 我想晚一点再换证。 — I want to renew it a bit later.

But 我想延期换证 is concise and natural, especially if the context is clear.

It is pronounced:

• wǒ xiǎng yánqī huànzhèng

Tones:

• 我 wǒ — 3rd tone
• 想 xiǎng — 3rd tone
• 延 yán — 2nd tone
• 期 qī — 1st tone
• 换 huàn — 4th tone
• 证 zhèng — 4th tone

A natural rhythm is:

• wǒ xiǎng / yánqī huànzhèng

In normal speech, 我 is often not pronounced with a full deep 3rd tone; it becomes lighter before another 3rd-tone syllable.

Yes, often you can, but the nuance is a little different.

• 延期 is a bit more formal and often used for official matters, deadlines, and procedures
• 推迟 is more general and conversational, meaning to put off or delay

So:

• 我想延期换证 sounds very suitable in an administrative context
• 我想推迟换证 is also understandable, but a little less official in tone

For licenses, permits, or formal renewals, 延期 is especially common.