This sample script, kindly provided by Mark Sibley shows how to change the case of a captured string.
Mark has written functions which change the case of a string to upper case, lower case or title case.

Either download the script, or paste the functions below into a LoadRunner script "as is" and then call them using the ConvertToUpper, ConvertToLower or ConvertToTitle functions.

For each function, the syntax is as follows.

ConvertToXXXX("sINPUT","sOUTPUT");
Where XXXX is Upper, Lower or Title
sINPUT is the name of the captured string.
sOUTPUT is the name of the new output string.

ConvertToUpper function
int ConvertToUpper(char * sInput, char * sNew)
{
 sInput = (char *)strupr(sInput);
 lr_save_string(sInput,sNew);
}

ConvertToLower function
int ConvertToLower(char * sInput, char * sNew)
{
 sInput = (char *)strlwr(sInput);
 lr_save_string(sInput,sNew);
}

ConvertToTitle function
int ConvertToTitle(char * sInput, char * sNew)
{
 int i = 0, s = 0, l = 0;
 char buf1[50];
 char buf2[2];
 char n;

 // Copy a single character into the address of [n]
 strncpy(&n,sInput+i,1);

 // Copy the single character into buf2
 sprintf(buf2,"%c",n);

 // Convert the contents of buf2 to uppercase
 strupr(buf2);

 // Overwrite the contents of buf1 with buf2
 strcpy(buf1,buf2);

 i++;
 while(i < strlen(sInput))
 {
  // Overwrite buf2 with one character
  strncpy(&n,sInput+i,1);
  sprintf(buf2,"%c",n);

  // If the previous character was a space then make the current character upper case
  if(s == 1){
   strupr(buf2);
   strcat(buf1,buf2);
   s = 0;
  }
  // Otherwise convert to lower case and concatenate the current character into the string buf1
  else{
   strlwr(buf2);
   strcat(buf1,buf2);
  }

  // If the current character is a space set the value of [s] to [1] so that the next character gets capitalised
  if(strcmp(" ",buf2)==0)
  {
   s = 1;
  }
  i++;
 }
 lr_save_string(buf1,sNew);
}