It is easy to do visa run through a land or air border for a longer stay in Vietnam when your current visa is about to expire. The processing works well for both tourist visa and business visa. You can come back straight away or a few days later depend on your schedule.
Keep in mind to check visa policy for the countries of your border run. Find here below the guide how to do Vietnam visa run, a list of land borders for Vietnam visa run, visa policy for Laos and Cambodia.