You can not extend your visa in Lhasa.

If you want to extend your visa, you can.

You need to extend your visa in China if you want to stay longer.

Just today I went to the immigration office to extend my visa and it seems no problems.

We could have extended our visa on arrival if we'd been staying longer than 30 days.

You can extend your visa in most places.

She went to Korea in 2004 for 3 months, but then returned because she could not extend her visa.

You can extend your visa up to three months at any police station after your arrival.

I have already extended my visa once.

Unable to extend her visa, she is deported back to Pakistan.