Removal Procedure

Remove the headliner. Refer to HEADLINER REPLACEMENT (PICKUP) or HEADLINER REPLACEMENT (UTILITY) or HEADLINER REPLACEMENT (EXTENDED CAB PICKUP) in Interior Trim.
Remove the sunroof drain hose from the front comer of the sunroof.

Fig 1: Removing Sunroof Drain Hose From Front Comer Of Sunroof - Front
Courtesy of GENERAL MOTORS CORP.
The left front sunroof drain hose is a part of the dome lamp wiring harness. You must unwrap the tape in order to remove the hose.

Fig 2: Removing Tape From Left Front Sunroof Drain Hose - Front
Courtesy of GENERAL MOTORS CORP.
Remove the rosebud clips from the front side door opening frame.
Remove the hose from the vehicle.

Fig 3: Removing Rosebud Clips From Front Side Door Opening Frame - Front
Courtesy of GENERAL MOTORS CORP.