how to skip to previous register in navision


help me to navigate on the navision tables register, where i need to update information that we has on the current register to previous register, i show the example

Line 1, has

Date1, date2, descripcion, value

Line 2 has

Date3 and other information, and need to take the date of this line and update on the Line 1 the date2 field.

Line1 09/02/13 11/02/13 09/02/13

Line2 12/02/13 15/02/13 12/02/13

Line3 16/02/13 16/02/13

the line 1 has 11/02/2013 from ponting date of Line2 less 1 day

i hope you apreciated help