Nikon D5500 - Manual (Page 152)

128 P, S, A, and M Modes
A
Adjusting Shutter Speed and Aperture
While exposure lock is in effect, the following settings can be adjusted
without altering the metered value for exposure:
Mode Setting
Programmed auto
Shutter speed and aperture
(flexible program; 0 116)
Shutter-priority auto Shutter speed
Aperture-priority auto Aperture
The metering method itself can not be changed while exposure lock is
in effect.