The SIM-card's name in sms

In every text I send stands the name of the SIM-card at the top of the message. I don’t want to read the name of the SIM-card everytime I read a text so how do I get it away? Have tryed to not write anything at all on the line for the SIM-card’s name but the phone doesn’t accept that.

Please see/add to the existing discussion here: