is it possible to read and write from/to file using only 1 assign()?

I mean something like:

```
assign(fl, 'file.txt');
reset(fl) 
// I know, that when I use reset - I have only read permission, 
// but is there any other option to read and write opening the file only once?
read(fl, variable);
write(fl, 'asdf);
close(fl);

```