Hi KVS,

Last date for  submission of online applications was 05.04.2018 (Thursday) without late fee.
whereas Last date for filing online Application with late fee of Rs.500/- till 10.04.2018.

The corrections can be made by following the procedure as prescribed by the Government. There are 2 categories for correction; Kindly refer to the link below to see which category you fall in and follow the procedure for the same:

http://www.sche.ap.gov.in/lawcet/PDF/APLAWCET2018_Corrections.pdf

Apart from that you may also want to refer:

Downloading of Hall-tickets from the website http://www.sche.ap.gov.in/lawcet
Date of AP LAWCET & PGLCET - 2018 Examination: 19-04-2018 (Thursday)
Time of Examination:  02:30 PM to 04:00 PM 

Hope this helps.