AN EMB140 HAD 2 DEFERRED ITEMS AUTOPLT AND YAW DAMPER EXPIRED. ACFT DISPATCHED WITH ONLY 1 SYS EXTENDED.

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ACFT WAS IN ZZZ WITH EXPIRED AUTOPLT AND YAW DAMPER MEL. WHAT WE HAD IN THE LOG AND TRACKING SHEET WAS AUTOPLT MEL. THE ACFT WAS LINKED UP TO AN XA30 DEP. OPS WILLING TO HOLD FLT TO GET MEL CLRED. AFTER THE PARTS CAME IN AND ZZZ1 MAINT INSTALLED THE COMPONENTS; THE FAULT WAS STILL THERE. SO I LOOKED OVER THE DATA FOR THE YAW DAMPER MEL AND FELT WE HAD ENOUGH TROUBLESHOOTING TO ASK THE MAINT CTLR FOR PERMISSION TO EXTEND THE MEL. WITH ALL THE TROUBLESHOOTING AND PARTS CHANGING ZZZ1 PERFORMED; THE MAINT CTLR APPROVED THE MEL EXTENSION. I CALLED THE ZZZ MAINT SUPVR TO COMPLETE THE PAPERWORK FOR THE MEL EXTENSION. (MAINT SUPVR) AND I TALKED THE PROC OVER AND EXTENDED THE YAW DAMPER MEL. THE PROB WAS THIS ACFT ALSO HAD THE AUTOPLT MEL THAT WAS INTERRELATED MEL TO YAW DAMPER THAT WAS EXPIRED. I JUST COMPLETED THE MEL EXTENSION PROC ON THE YAW DAMPER MEL; AND NOT THE AUTOPLT MEL. THE ACFT FLEW 1 FLT LEG WITH AN EXPIRED MEL. BOTH MEL'S SHOULD HAVE BEEN EXTENDED. IT IS A MATTER OF NOT COMPLETING BOTH EXTENSIONS. NO FAILURES RPTED BY FLT CREWS. I WAS JUST TRYING TO PREVENT A FLT CANCELLATION.