---
title: "system.mes.trace.modifyOperation"
id: "system-mes-trace-modifyoperation-userid-name-begindatetime-enddatetime-equipment-workorder-material"
project: "MES User Manual"
url: "https://docs.sepasoft.com/articles/user-manual/system-mes-trace-modifyoperation-userid-name-begindatetime-enddatetime-equipment-workorder-material"
updated: 2026-10-01T18:15:14Z
---
# system\.mes\.trace\.modifyOperation
**Sepasoft MES Module Suite**
### system.mes.trace.modifyOperation
This method accepts keyword arguments. Modify an existing operation that was recorded with a user-provided id.
system.mes.trace.modifyOperation(userid, name, beginDateTime, endDateTime, equipmentPath, materialIn, materialOut, workOrder, personnel, supplementalEquipment, operationCustomProps, removeLot)
|  | **Version specific**
**MES 3.81.6 RC 3** **and later**
For version downloads, go to [https://www.sepasoft.com/downloads/](https://www.sepasoft.com/downloads/). |
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|  | Version specific behavior:
- As of MES 3.81.10 SP7 system.mes.trace.modifyOperation returns previous/next lots when deleting a material lot or changing the material of the lot. system.mes.trace.deleteOperation also deletes the material that was created by the operation.
- As of MES 3.81.11 SP7 system.mes.trace.modifyOperation increments the lot sequence number when the in lot and out lot are the same or when the out lot already exists.
|
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Syntax
system.mes.trace.modifyOperation(userid, name, beginDateTime, endDateTime, equipmentPath, materialIn, materialOut, workOrder, personnel, supplementalEquipment, operationCustomProps, removeLot)
* Parameters
**userid**; string Required This is a user-provided id that is used to specify the operation to modify.
**name** string Optional. Optionally include this if changing the name of the operation as it appears in the trace graph. Default: None
**beginDateTime** Optional: Optionally include if changing the begin date-time of the operation. Default: None
**endDateTime** Optional: Date Optionally include this if changing the end date-time of the operation. Default: None
**equipmentPath** Optional: String Optionally include if changing the equipment path where the operation occurred. Default: None
**materialIn** Optional: PyList
Only include material in items that are being changed. If modifying an existing material entry, the id is required. Otherwise, it is optional. Lot Array Entry: {'delete':False, 'UserID':'', 'Name':'', 'LotNo':'', 'MaterialName':'', 'Quantity':, 'UOM':'', 'Status':'', 'BeginDateTime': , 'EndDateTime': , 'EquipmentPath':'', 'ManifestName':'', 'LotCustomProperties': {}, removeLot}
Default: None
**materialOut**Optional: PyList
Only include material out items that are being changed. If modifying an existing material entry, the id is required. Otherwise, it is optional. Lot Array Entry: {'delete':False, 'UserID':'', 'Name':'', 'LotNo':'', 'MaterialName':'', EquipmentPath':'', 'ManifestName':'', 'Quantity':, 'UOM':'', Status:'', 'BeginDateTime': , 'EndDateTime': ,'LotCustomProperties': {}} LotCustomProperties Array Entry: {'Name':'', 'Value':, 'removeLot':True}
Default: None
**personnel** Optional: PyList
Only include personnel items that are being changed. If modifying a personnel entry, the id is required. Otherwise, it is optional.Personnel Array Entry: {'delete':False, 'UserID':'', 'Name':'', 'Person':'', 'Quantity': , 'UOM':'', 'BeginDateTime': , 'EndDateTime':}
Default: None
**supplementalEquipment** Optional: PyList
Only include supplemental equipment items that are being changed. If modifying a supplemental equipment item, the id is required. Otherwise, it is optional.Equipment Array Entry: {'delete':False, 'UserID':'', 'Name':'', 'EquipmentName:'', 'Quantity': , 'UOM':'', 'BeginDateTime': , 'EndDateTime':}
Default: None
**operationCustomProps** Optional: PyList
An optional array defining the custom properties associated with the operation. Custom Property Array Entry: {'Name':'', 'Value': }
Default: None
**removeLot** Boolean - Optional: Defaults to True. When true it deletes the Material Lot if the Material Lot is set for deletion. If set to false it only removes the reference from the segment. **Included in MES 3.81.10 SP9 and later.**
* Returns
Returns previous and next lots when removing or changing the material of the lot.
* Scope
All
|  | In MES 3.81.12 SP4, MES 4.83.1 SP4, and later, a material, person, or supplemental equipment added with `modifyOperation` and no dates uses the first date that is set: the date passed on the operation, then the date stored on the operation’s response segment, then the current time. |
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**Sepasoft MES Module Suite**