Can my friend renew her tourist visa extension at immigration more than once in Thailand?

Hello! My friend is from the UK (she is British) and she is staying here for 4 months. She is on a tourist visa which has to be renewed every 30 days. She has already renewed it once at immigration here, and will fly out for the second time to get another 30 day visa stamp. Is it possible in 30 days time for her to get an extension again at immigration like she did the first time? (basically, can you go to immigration more than once to get an extension?)