Linked List Deletion

[MasterAchilles]

My cancel function stops working if I delete the node. Any hints you can give me as to why?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef char FName[30];
typedef char LName[30];

typedef struct PassengerInfo
{
       FName   firstname;
       LName   lastname;
       struct PassengerInfo *Link;
} FlightData;

             typedef FlightData *FlightPointer;
             FlightData *Passenger, *PassengerData;

void Book(FlightData **PassengerData, char *first, char *last)
{
     FlightData *Passenger, *Locate;
     
     // Allocate new nodes for Passenger with firstname & lastname and Link == NULL 
     Passenger = (FlightData*)malloc(sizeof(FlightData));
     strcpy(Passenger->firstname, first);
     strcpy(Passenger->lastname, last);
     Passenger->Link = NULL;
     
     // Check to see if PassengerData is empty.
     if ((*PassengerData) == NULL)
     {
           *PassengerData = Passenger;
     }
     
     else
     {
         // Locate last node
         Locate = *PassengerData;
         
         while (Locate->Link != NULL)
         {
               Locate = Locate->Link;
         }
         
         // Link node to end of list.
         Locate->Link =  Passenger;
     }
}

void Cancel(FlightData **PassengerData, char *first, char *last)
{
     FlightData *CurrentNode, *Temporary;
     CurrentNode = NULL;
     Temporary = NULL;
     
     // Do nothing if PassengerData is empty
     if ((*PassengerData) == NULL)
     {
		printf("\nThere are no passengers booked for this flight.\n");
     }

	if(strcmp(((*PassengerData)->firstname), first) == 0)
	{
		if(strcmp(((*PassengerData)->lastname), last) == 0)
     		{
			Temporary = (*PassengerData);
            	(*PassengerData) = (*PassengerData)->Link;
            	free(Temporary);
            	printf("\nBooking has been cancelled for %s, %s.\n", last, first);
		}	
     }

	// Initialize pointers and make them point to first node.
      CurrentNode = (*PassengerData);
	
	while(CurrentNode->Link != NULL)
	{
		if(strcmp((CurrentNode->Link->firstname), first) != 0)
		{
			CurrentNode = CurrentNode->Link;
		}
	}
	
	if(CurrentNode->Link == NULL && (strcmp((CurrentNode->Link->firstname), first) != 0))
	{
		printf("\nThat passenger is not booked for this flight.\n");
	}
	
	Temporary = CurrentNode->Link;
	CurrentNode->Link = CurrentNode->Link->Link;
	free(Temporary);
	printf("\nBooking has been cancelled for %s, %s.\n", last, first); 
}

FlightData *Confirm(char *first, char *last, FlightData *PassengerData)
{
          FlightData *Passenger;
          
          Passenger = PassengerData;
          
          while (Passenger != NULL)
          {
                if (strcmp((Passenger->firstname), first) == 0)
                {
				if(strcmp((Passenger->lastname), last) == 0)
				{
					printf("\n%s, %s is booked on this flight.\n", last, first);
                      		break;
				}
				
				else
                		{
					Passenger = Passenger->Link;
                		}
          		}
		}
          
          if(Passenger == NULL)
          {
			printf("\n%s, %s is not booked on this flight\n", last, first);
	    }
}

void Display(FlightData *PassengerData)
{
     FlightData *Passenger;
     
     printf("\nPassenger List: \n");
     
     Passenger = PassengerData;
     
     while (Passenger != NULL)
     {
           printf("\n%s, %s\n", Passenger->firstname, Passenger->lastname);
           Passenger = Passenger->Link;
     }
     
}

int main(void)
{
    FILE* ifp;
    FlightData *PassengerData;
    
    PassengerData = NULL;
    
    	char first[30];
	char last[30];
	char action[15];
	char filein[25];
	char* remove;
	
	printf("Please enter the name of the file to be read.\n");
	fgets(filein, sizeof(filein), stdin);
	
	if((remove = strchr(filein, '\n')) != NULL)
      {
		*remove = '\0';
      }
	
	ifp = fopen(filein, "r"); 
	
	while (!feof(ifp))
	{
          fscanf(ifp, "%s\n", &action);
          
          if (strcmp(action, "BOOK") == 0)
          {
                fscanf(ifp, "%s %s", &first, &last);
                Book(&PassengerData, first, last);
          }
          
          else if (strcmp(action, "CANCEL") == 0)
          {
               fscanf(ifp, "%s %s", &first, &last);
               Cancel(&PassengerData, first, last);
                     
          }
          
          else if (strcmp(action, "CONFIRM") == 0)
          {
               fscanf(ifp, "%s %s", &first, &last);
               Confirm(first, last, PassengerData);
          }
          
          else if (strcmp(action, "DISPLAY") == 0)
          {
               Display(PassengerData);
          }
          
          
    } 
    
	system("pause");
	return 0;
}

[zacs7]

A few things,

* Don't use feof() to control a loop
* Don't cast malloc()
* Check the value of the pointer returned by malloc() before dereferencing it (ie it's not NULL)
* Check the return value of fopen() to ensure it didn't failed (ie, not NULL)
* Stick to spaces OR tabs for indenting not both
* Don't typedef arrays, it's confusing as hell

if(CurrentNode->Link == NULL && (strcmp((CurrentNode->Link->firstname), first) != 0))

Naughty, I think you mean CurrentNode->Link != NULL && ...

I assume FlightData.Link is a pointer to the next node in the list? Other than that, Cancel() is a bit confusing and I'm tired
Have you tried using a debugger?