United Airlines Friday announced the schedule for resumed service between San Francisco and Shanghai with twice-weekly flights starting from July 8, according to a release by the airline.

United Airlines would operate service on Wednesdays and Saturdays from San Francisco to Shanghai. And the return flights would take off on Thursdays and Sundays, said United Airlines.

The service resumption by United Airlines between San Francisco and Shanghai is part of the latest governmental arrangement between the United States and China. Currently, only four round-trip flights would be allowed from each side each week.

Still, United Airlines continues to sell tickets for flights from San Francisco to Shanghai on other dates as early as August 18 but not Wednesday or Saturday, according to the website of United Airlines.

Customers who buy San Francisco-Shanghai tickets on other dates rather than Wednesday or Saturday won't be able to fly if there is no policy change from both governments, a customer service agent with United Airlines told Xinhua.

The tickets on other dates won't be transferred to scheduled dates automatically, said the agent.

This means that clients who purchase such tickets on other dates face a significant risk of cancelation of their trips or financial inconveniences.

In response to the arrangement of both governments, Delta Air Lines has started to execute flights between Seattle and Shanghai starting from June 25 to Oct. 24 in the first phase.