Can I renew a working visa 40 days before its expiration if I will be abroad during that time?

The standard rule at most immigration offices in Thailand is that you can apply for a visa extension when you have 30 days or less remaining on your current visa. However, in certain places like Chiang Mai, Bangkok, and Phuket, the limit is extended to 45 days. You may be able to submit your extension application with all necessary documents and proof of your trip abroad, but it may depend on the specific immigration office.