China Visa Renewal and Extension
Generally speaking, it is not possible to renew, extend a China visa or change it into another type once it is issued. However, if you want to spend more time there, want a multiple-entry visa, or need to have a different type of visa, you can - in many circumstances - apply within China.
Currently, it seems that one month is the standard period for regular tourist visa extension. However, the accumulated length of the extended stay cannot exceed the duration of stay on your original visa.
Where to extend or renew China visa?
The procedure is very similar to applying outside through Chinese embassy, but you must go to the Public Security Bureau (PSB) Exit and Entry Administration office of county level or above. Smaller centers might not have good English speakers so it is a good idea to take a Chinese friend with you if you can. Ask at international hotels if you are not sure where the PSB Exit and Entry Administration office is.
When to apply for China visa renewal and extension?
According to the regulations, you have to submit application for extension at least 7 days before your visa expires. The PSB officers will issue you with a receipt once they accept your application and make the final decision within 7 days. If you apply too late, you may overstay and are subject to a fine and possible deportation.
The new visa runs from the date of issue (a small difference compared with those issued outside China which do not start until entry) and the old one is cancelled at the same time. So, you cannot have two concurrent visas.
How to extend or renew my China visa?
The required documents you must prepare in advance include your passport, a recent passport style photo, a registration form of temporary residence, and proof about reasons for extending or renewing your China visa, for example, if you apply for tourist visa extension, you need to submit a travel itinerary.
In normal cases, the applicant should come in person to the PSB Exit and Entry Administration office to submit the application. Upon arrival, complete a visa application form and attach your photo onto it. Then submit the application.
In the following situations, the applicant can have others or an agency submit the application:
1) The applicant is under 16 or more than 60 years old, or with mobility difficulties.
2) The applicant is not a first-time visitor to China and has a good stay record for the past visits.
3) There is an inviting entity or individual funding the applicant’s visit.
How to get the registration form of temporary residence for overseas visitors
The residency registration comes from the regulation that all foreigners must register their accommodation details within 24 hours after entering China.
If you are staying in a hotel certified to accommodate foreigners, it can provide you with a hotel accommodation registration slip. If not, you must obtain an accommodation registration printout from the police station for the area you are living in and where you should already have registered. So if you are staying in a non accredited hotel or with friends or in an apartment but have not registered, you should either register or stay in an accredited hotel for one night in order to get the slip.
How much does it cost to extend a China visa?
For nationals of most countries, the fee is CNY 160. For some countries, the fee may differ. US citizens need to pay CNY 760 for an extension while UK citizens need CNY 469.
Can a 10 years, multiple (M) entries L VISA be extended? Or is it one of the type of VISA you have to leave the country and re-enter to reset your stay duration?
It's possible to get the visa extension. It will last for 30 days. According to the visa officer you can only extend once. Then you have to get out of the country to reset your visit duration.
As additional information since I didn't find it anywhere, the visa extension comes as a new visa taking one full passport page. The existing visa is left untouched.