I need a variable whose value can be changed based on the if conditions. 

Eg: 

I have 3 input variables (inputVar1, inputVar2, inputVar3) and 3 output variables (outputTempVar1, outputVar1, outputVar2)

I need to copy these input variables to output variables based on some condition.

Conditions:
If all the 3 input variables are present, map inputVar1 -> outputTempVar1, map inputVar2 -> outputVar1 and map inputVar3 -> outputVar2. 

If there are only two input variables present (inputVar1, inputVar2), map inputVar1 -> outputVar1 and map inputVar2 -> outputVar1.

If there is only one input variable is present (inputVar1), map inputVar1 -> outputVar1.   

So output variables get their values based on input variable's presence (not empty).

So can I change the value of the output variable? How can I achieve the above in xslt 1.0.