An organ tuning? First you have to tell us about the organ. I can imagine several hundred or even thousands for a large pipe organ. Modern digital organs won't require tuning at all since it is all sample driven (though voicing to the room is very important).
An old analogue (which I imagine this is) with off-set four octave keyboards, will probably require more work than "tuning" the oscillators. Most likely it will require replacement of some capacitors and/or other components. Almost certainly will require cleaning the key contacts as well. (I can't imagine why the upper manual would be 49 notes.)
Your first problem is finding someone who can and does work on them.
Then again, if your assessment of "the strings need to be raised" is based on Celeste stops, it may not need service. A Celeste is detuned slightly to create a chorus effect when used in conjunction with other stops.
Mutations (5 1/3, 2 2/3, 1 1/3, 1 3/5) it may not need service at all. Those are tuned to harmonics of the fundamental, and are never used alone as a speaking stop.
Mixtures (labeled with roman numerals III, IV, or V) are made up of (3, 4 or 5) ranks of pipes intended to sound together usually use octaves and fifths (or occasionally thirds) in almost every case the mixture will fold back on itself -- as you run out of "pipes" at the top, those an octave lower will begin to speak.
... piano tuners are becoming rare enough, qualified organ tuners more so, people working on transistor and tube organs are perhaps a 10th of that lot.
EDIT: Aéoline, Aéoline céleste, Cello, Viol da Gamba, Salicional, Voix céleste are all examples of string stops; there are probably many more named on Theater organs.