Thank Andre, I have done, but new challenge is here,

As per the code, I have set as if expiry status got expired case, expiry date got disabled means not able to modify.
Note: by writing code i.e., disable fields on a form for a particular role.
/* container roleNames;
SecurityRole role;
SecurityUserRole userRole;
UserInfo userInfo;*/
//select userRole where userRole.SecurityRole == "System Administrator";
while select firstonly role
exists join userRole
where role.RecId == userRole.SecurityRole
&& userRole.User == curUserId()
//{
//roleNames += [role.Name];
//}
//if((confind(roleNames, “System Administrator”)) || (confind(roleNames, “SalesTableForExpiryDate”)))
//if(conFind(roleNames, "System administrator"))
//|| (conFind(roleNames, "SalesTableForExpiryDate”)))
if(role)
{
salestable_ds.object(fieldNum(SalesTable, ExpiryDate)).allowEdit(true);
}
else
{
salestable_ds.object(fieldNum(SalesTable, ExpiryDate)).allowEdit(false);
}
not worked clearly, what I want to do is I must create a role (customised role) that particular role assigned to the user, then he can able to modify (enable the date field) the date this is my customisation.
my concern is how to assign that particular role use to the current code.
Regards,
Vinilkumar.