#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e2 + 5;
int t, n, m; char a[N][N], r[N][N];
const int dx[4] = {-1, -1, 0, 0};
const int dy[4] = {-1, 0, -1, 0};
bool same(int x1, int y1, int x2, int y2) {
	return (a[x1][y1] == a[x2][y2]);
}
bool equal(int x1, int y1, int x2, int y2) {
	return (same(x1, y1, x2, y2) || a[x1][y1] == '?' || a[x2][y2] == '?');
}
bool work(int x1, int y1, int x2, int y2) {
	return equal(x1, y1, x2, y2) && equal(x1, y2, x2, y1) && (!same(x1, y1, x1, y2) || !same(x1, y1, x2, y1) || !same(x2, y1, x2, y2) || !same(x1, y2, x2, y2));
}
char near(int x, int y, int x1, int y1, int x2, int y2) {
	int xx = x, yy = (y == y1 ? y2 : y1);
	return a[xx][yy];
}
int check(int x, int y) {
	if(a[x][y] != '?') return 1;
	for(int i = 0; i < 4; i++) {
		int nx = x + dx[i], ny = y + dy[i];
		if(nx < 1 || nx + 1 > n || ny < 1 || ny + 1 > m) continue;
		// cout<<"in "<<nx<<" "<<ny<<endl;
		int b = 1;
		for(int xx = 0; xx < 2 && b; xx++) for(int yy = 0; yy < 2 && b; yy++) {
			int tx = nx + xx, ty = ny + yy;
			if(x != tx && y != ty && a[tx][ty] == '?') b = 0;
		}
		if(!b) continue;
		if(work(nx, ny, nx + 1, ny + 1))
			if(a[x][y] != '?' && a[x][y] != near(x, y, nx, ny, nx + 1, ny + 1)) {
				// cout<<"check "<<x<<" "<<y<<" = "<<0<<endl;
				return 0;
			} else {
				a[x][y] = near(x, y, nx, ny, nx + 1, ny + 1);
				// cout<<"a["<<x<<"]["<<y<<"] = "<<a[x][y]<<endl;
			}
	}
	// cout<<"check "<<x<<" "<<y<<" = "<<1<<endl;
	return 1;
}
void solve() {
	cin>>n>>m;
	for(int i = 1; i <= n; i++) for(int j = 1; j <= m; j++) cin>>a[i][j];
	int b = 1;
	for(int i = 1; i <= n && b; i++) for(int j = 1; j <= m && b; j++) b = min(b, check(i, j));
	for(int i = n; i >= 1 && b; i--) for(int j = m; j >= 1 && b; j--) b = min(b, check(i, j));
	if(!b) {
		cout<<"NO"<<endl;
		return;
	}
	cout<<"YES"<<endl;
	// for(int i = 1; i <= n; i++) {
	// 	for(int j = 1; j <= m; j++) cout<<a[i][j];
	// 	cout<<endl;
	// }
	while(1) {
		memcpy(r, a, sizeof(r));
		b = 1;
		for(int i = 1; i <= n && b; i++) for(int j = 1; j <= m && b; j++) {
			b = min(b, check(i, j));
			if(a[i][j] == '?') a[i][j] = ((rand() % 2) ? 'B' : 'W');
		}
		for(int i = 1; i <= n && b; i++) for(int j = 1; j <= m && b; j++) b = min(b, check(i, j));
		if(b) break;
		memcpy(a, r, sizeof(a));
	}
	for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) cout<<a[i][j];
		cout<<endl;
	}
}
signed main() {
	srand(time(0));
	cin>>t;
	while(t--) solve();
}