I have created a mesh in two parts separately in ABAUQS and have ended up with two sets of node numbers along a common edge. Is there any alternative to editing the *.inp file to replace one set of node numbers by the other set in the element-nodal connectivity list ie element entries?

Yes. Use the TIE option available under MPC (Multi Point Constraint) to tie the respective nodes as illustrated in the figure below :

*MPC
TIE,  100, 200
TIE,  101, 201
         ......
TIE,  104, 204

This would then treat these pair of nodes as identical ie. they will have the same nodal variables. This can also be useful in situations where the mesh used in an axisymmetric analysis is generated from a single surface wrapped around (rather than using the axisymmetric elements available in ABAQUS). See figure below. Then the TIE option could be used along line joining the 2 edges (and the 2 sets of nodes).

If there are several such nodes these could be grouped together into sets and the TIE option specified with a single data line. Here the corresponding nodes should appear in the correct order. 

*NSET, NSET=TOP
 100,  101,  102,  103,  104
*NSET, NSET=BOT
 200,  201,  202,  203,  204
*MPC
 TIE, TOP, BOT