Other possibility, use URM, and one save. From a superficial look at the code (for the patch), with whom is going to be the date is decided by to whom you had replied when Myriam came back from the hospital (and from some previous interactions, e.g. if you sent the cops to Hell, cannot expect to go to dinner with them), in practice, is a set of variables, only one of which (or none) should be true.
So, depending on your previous choices (if you already closed a path, or not), it is possible to take a later save, changed the variable that says to whom Myriam replied, and get that dinner - though do a save before you start playing with the variables, in case you screw up a variable value and have to go back.