[Q] unlocking sprint note 3 with msl code

[topdawg_b]

I am trying to swich my sprint note 3 to straight talk.
I spoke with sprint and they told me they could not unlock international sim because it is done online and the phone i bought is not currently active. they also said i could unlock the phone with a master subsidy lock code. i acquired the code but i have no method in which to use it.
is there a number i can punch in with this code to unlock the sim from saying invalid sim?