That won't help, because that is not where the partyname is defined.
@OP:
Susan is correct, by default it should NOT return a team name when there is only one actor in the party - you can see that in the script "Game_Party", line 131 following - if there is only one battler, then only that battler's name (without "Party") will be returned.
If that does not happen to you, then you modified or added scripts to change that. Please link us to all scripts you're using, then we can tell you what to change.