I have resolved most but still could use help setting the OBX5 field

I  parsed out the OBX 5 , "REASON FOR REQUEST".

Exmaple:

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|2|REASON FOR REQUEST: Item Number: 00801741016608||||||O

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|3|REASON FOR REQUEST:      Transaction Date/Time: 01/22/2025 17:45||||||O

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|4|REASON FOR REQUEST:      Station Number: 757||||||O

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|5|REASON FOR REQUEST:      Item Description: Plug Surgical 1.3in Groin Monofilament ||||||O

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|6|REASON FOR REQUEST: Nonabsorbable Perfix Polypropylene Medium Taper 1.55in Sterile Hernia ||||||O

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|7|REASON FOR REQUEST: Repair 0112760||||||O

Now , I need to replace the OBX 5 with the remainder

Example:

Before:

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|4|REASON FOR REQUEST:      Station Number: 757||||||O

After:

OBX|1|TX|2000.02^REASON FOR REQUEST^AS4|4|      Station Number: 757||||||O

spaces don't matter