Restoring original stack variable in IDA Pro?

I would like to convert an instruction like:
lea ecx, [esp+150h+var_13E+2]
to:
lea ecx, [esp+14h]
I know it’s possible to do this with the key K. But I’m writing an IDAPython plugin that needs an automatic conversion of instructions like the one above.

Edit:
Are there any idaapi functions to do this?

idaapi.op_seg(idc.get_screen_ea(), -1)
idaapi.op_stkvar(idc.get_screen_ea(), -1)