Change a Bool in a BP which is in a Sub-level from the persistent level

Should I call an event to change it from inside PodBP OR should I just SET>DaVar

Edit:
In the persistent Level BP:

When I SET DaVar I get an error (accessed none…) and nothing happens

When I call a function “ChangeBool” inside PodBP NO error and nothing happens

the way I do it now is I create a var in the lvl BP and assign PodBP to it. Also all my vars are Editable and exposed at spawn .