Make, model, size?
Turn the tv on its axis with respect to the north pole to change the
tilt.
If it were a higher end larger tv set 32" or bigger, it might have a
tilt correction circuit built in, check the owners manual. If not
there is not way to correct for the tilt.

A 27" size tv can have up to 1/2" tilt from the earth's magnetic field
depending on orientation and location of the tv set.