Passenger feedback to staff (SBW) that car 2610 'B4' train doors did not open. Staff (MSL) checked a nd confirmed. ~~~~~ 2610 Pax feedback to staff (SBW) B4 train doors did not open. Staff (MSL) checked and confirmed.  2610 B4 door found RHS outer roller delaminated - replaced with new roller. Security/function check - OK. Cleaned J-rail/gude rail & no FOD was detected. Checked weather strip condition, door gap = 63.7mm, door static test & door push/pull, no wobbling found - OK. Door cyclic test 15x & DIR extinguished when doors were closed.  Alan/Kamarul/Shafie 45138