As far as I know, there are different services you can purchase and I would say it is wise to speak with the calibration lab you have selected to be aware of the type of services they provide and how they perform TE verification, calibration and repair.
Try to contact one of their repair technicians. These guys are more likely to discuss how the process is performed and will provide detailed information.
Different levels of servicea) The vanilla service level is only the 'verification' that checks whether your TE meets its specifications. If so, you get a one-page report with a (nice) stamp, brand, model and serial number of your TE.
b) For an additional charge, you can get a detailed verification report which lists all the tests/ranges that have been verified, their actual deviation and the measurement uncertainty.
The detailed verification report should normally include a list of all equipment used by the calibration laboratory to perform this verification. For each device, you must have its brand, model number, serial number, last calibration date, next calibration due date.
c) In case the result of at least one test is FAIL, the TE enters a 'calibration' process, where new cal parameters are calculated and stored, or for vintage stuff, the required trimmers are adjusted manually. Once the calibration OP estimates its work done, the TE is handed back to the 'verification' department. In that case, if you ask for b), the
report usually includes the first verification results (having at least one failed test) and the verification results after calibration. The latter will have to show that all of the verification tests are PASS.
e.g. : I recently had to sent my MW powermeter back to the manufacturer for cal service : the detailed report they sent me contains 22 pages.
d) In the event that the 'calibration' cannot be carried out successfully, the owner is informed of this situation and can request a 'repair'. The owner can also refuse the repair and the TE is returned to him as is, for a nominal fee.
A 'repair' is necessary if a part has drifted so far that the span of the calibration parameters cannot bring the TE back to specification.
Calibration will also be impossible if a part/assembly is defective, if connectors or solder joints have shaky contacts, if essential accessories are missing, if traces have disappeared due to electrolyte spillage, if mains overvoltage or a shorted Tantalum capacitor killed the PS, lightning damage, improper use of the TE which fried the whole input board, equipement was drowned, stored/used in a hazardous/corrosive environement, internal hard disk failure, backup battery empty leads to the loss of all cal coeficients, if there is mechanical damage (connectors, screen, front plate, case, cables,...), in case of multiple damage because the device fell from the moving truck or even if the owner tried an in-house repair and opened the TE with a crowbar without removing the screws. These kinds of things happen.
If the owner wants the TE repaired, the repair technician will estimate the cost of the 'repair' and send a pro-forma invoice for it.
Once this pro-forma invoice has been accepted by the owner, the TE is repaired and then handed over to the 'calibration' department c). Once the latter has been carried out, the TE goes back to the 'verification' departement for a) or b).
The owner can request detailed information on what was actually repaired and what parts/assemblies were replaced. This type of information can be printed in the detailed report, if provided, or in the final invoice, which includes all repair, calibration and verification costs.