String Manipulation help

[SkOODaT]

need a bit of help with these "guild traders" as soon as a guild reserves it changes the caption to "guild trader (GUILDNAME)"

My vendors addon plots the npcs by Add("PIN_GUILDTRADER", "Guild Trader")

Is thier a way for me to have the sting post what ever it finds i thought it was something like

Add("PIN_GUILDTRADER", "Guild Trader%s")

thank you