record locking using a parameter value

[jensonchandy]

hi friends

i had gone thru the record locking
first i'll tell u what i need
i'm having a form for timesheet entry
there r two persons going thru the form
first one person enter the data
and the second one cross check it
what i need is whatever the second person had checked that should be locked...it should be done using a date parameter...if i enter a date as a parameter value records upto that date chould be locked....
is there any way to do this...
help needed

regards
jenson